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Author: search.filters.author.Kirasamuthranon, Lerson

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    DSSZ-SM: A Simplified Chirp Coding Scheme with Inherent Clock Synchronization
    (2026-06-01)
    Kirasamuthranon, Lerson
    ;
    Koseyaporn, Jeerasuda
    ;
    Wardkein, Paramote
    This study proposes a novel double-slope chirp symbol, termed double-slope start zero stop minimum (DSSZ-SM), for efficient data communication. Unlike conventional chirp coding, which often involves complex generation and synchronization, the DSSZ-SM provides a simpler structure with inherent clock synchronization using a PWM-based generator. System performance is evaluated through analysis and simulations over additive white Gaussian noise (AWGN) and Rayleigh fading channels. Two asynchronous decoding methods, with and without an integrator, are compared. Results show that the non-integrator approach achieves lower error rates under both channel conditions. The proposed DSSZ-SM offers a simplified and robust alternative for efficient data communication.
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    Design and Analysis of a Miniaturized Triple-Band Implantable Antenna for Biomedical Applications
    (2025-01-01)
    Changkol, Porworamon
    ;
    Mongkolcharoensri, Sopanarin
    ;
    Kirasamutranon, Keerati
    ;
    Wongchampa, Paleerat
    ;
    Kirasamuthranon, Lerson
    This paper presents the design and simulation of a compact F-shaped patch antenna for implantable biomedical applications. The antenna is optimized to operate at three key frequency bands: 401–406 MHz (MICS), 1.395–1.432 GHz (WMTS), and 2.4–2.5 GHz (ISM). A progressive design approach—starting from an I-shape and evolving to an F-shape with a shorting pin—was employed to achieve multiband operation and circular polarization. Full-wave simulations were performed using CST with a realistic three-layer human tissue phantom based on the Zubal model. The final design exhibits return loss below –10 dB, stable VSWR, gain consistency, and radiation efficiency above –15 dB across all bands. Radiation pattern analysis shows a transition from omnidirectional to directional as frequency increases. The antenna also maintains robustness against implantation depth variation and supports communication distances up to 15 meters. These results demonstrate the antenna’s potential for reliable, efficient in-body wireless communication.
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    Novel Double Slope Frequency Shift Chirp Symbol
    (2024-01-01)
    Kirasamuthranon, Lerson
    ;
    Wardkein, Paramote
    ;
    Koseeyaporn, Jeerasuda
    One of the most significant concerns in serial digital communication is the synchronization of data bits between the transmitter and receiver. Therefore, the preferred coding symbols should contain an inherited clock signal. The cyclic-shift chirp, which is primarily used in long-range systems, employs a single slope in a symbol, which contains few information for synchronization. Hence, two new forms of cyclic-shift chirp symbols are proposed herein. The associated coding schemes are based on the use of a dual slope within one symbol. Synchronization is inherited in the coding symbol using a dual slope. Additionally, both proposed coding schemes utilize the same decoding technique. The decoded chirp symbol is in the form of a pulse width modulation signal, which can be used for synchronization and retrieving data bits from their duty cycle. The simulation results show that the coding and decoding processes of the proposed coding schemes align with those of a theoretical framework. The error performance analysis for the proposed detection scheme is given and the results of error probability analysis are consistent with the simulation results. Moreover, under a Rayleigh fading channel, the proposed coding schemes provide superior performance compared with other comparable coding schemes.
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    Coding and Coherent Decoding Techniques for Continuous Single Slope Cyclic Shift Chirp Signal
    (2023-06-01)
    Kirasamuthranon, Lerson
    ;
    Wardkein, Paramote
    ;
    Koseeyaporn, Jeerasuda
    Chirp signals are currently widely used in broad-band and spread spectrum communications due to their ad-vantageous features, such as immunity to fading noise, low power consumption, consistent long-range transmission, and constant bandwidth. As a result, they are applied at the physical layer of the Internet-of-Things (IoT). This study proposes two techniques for encoding and decoding 4-cyclic shift chirp symbols, based on addition and subtraction oper-ations. The proposed techniques have simple structures that can be easily implemented using analog circuits. The pro-posed encoding techniques reveal obviously the relationship between cyclic-shift chirp symbols and pulse modulating signals (PWM, PPM, and PAM), which is rarely discussed in prior research. Moreover, the circuit for encoding and decoding of the proposed technique is implemented by dis-crete commercial devices at low frequency (25–35 kHz) which is suitable for sonar and communication under water; however this proposed technique is not limited to only low frequency but is also capable of being used in high frequency band as well which experimental and simulation result show agreeing well with each other.
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    QPSK modulator with continuous phase and fast response based on phase-locked loop
    (2017-06-01)
    Kirasamuthranon, Lerson
    ;
    Koseeyaporn, Jeerasuda
    ;
    Wardkein, Paramote
    Among M-phase shift keying (M-PSK) schemes, quadrature phase-shift keying (QPSK) is used most often because of its efficient bandwidth consumption. However, in comparison with minimum-shift keying, which has continuous phase transitions, QPSK requires a higher bandwidth to transmit a signal. This article focuses on the phase transitions in QPSK signals, and a QPSK modulator based on a phase-locked loop (PLL) is proposed. The PLL circuit in the proposed system differs from that of conventional PLL circuits because a three-input XOR gate and a summing circuit are used. With these additional components, the proposed PLL provides a continuous phase change in the QPSK signal. Consequently, the required bandwidth for transmitting the QPSK signal when using the proposed circuit is less than that for a conventional QPSK signal with a discontinuous phase. The analytical results for the proposed system in the time domain agree well with the experimental and simulation results of the circuit. Both the theoretical and experimental results thus confirm that the proposed technique can be realized in real-world applications.