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    Performance of Smart Antenna Under Different Fading Conditions
    (2022-05-01)
    Senapati, Anupama
    ;
    Patro, B. Shivalal
    ;
    Sooksood, Kriangkrai
    ;
    Mohapatra, Sushanta Kumar
    Optimizing the current distribution of an evenly spaced antenna array has shown to be an efficient approach for reducing side lobe levels. In this article, the Tchebyscheff distribution-based antenna array synthesis approach is combined with an adaptive signal processing algorithm for beamforming and side lobe level reduction in smart antennas in various fading situations. The performance of smart antennas in uniformly spaced linear, planar, circular, and semi-circular arrays are evaluated. The presence of Rayleigh and Rician channels is examined in the network. The least mean square (LMS) and normalised least mean square (NLMS) algorithms are applied as adaptive algorithms. In fading environments, the NLMS algorithm with Tchebyscheff distribution outperforms than the LMS algorithm with Tchebyscheff distribution, with a side lobe level decrease of 11.23 dB. The lowest side lobe achieved with the NLMS algorithm with Tchebyscheff distribution is − 45.59 dB for uniform planar array.
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    A triple-band printed microwave absorber for WLAN/WiMAX applications
    (2017-10-19)
    Khoomwong, E.
    ;
    Soemphol, C.
    ;
    Phongcharoenpanich, C.
    This paper presents a triple-band printed-circuitboard microwave absorber for applications in 2.4GHz WLAN and 3.5/5.8GHz WiMAX bands. The absorber consists of simple geometries with tuning elements and chamfering, which can significantly reduce the modeling errors. The study and design processes are based on numerical simulations. The simulated results show the absorption bandwidths (at 50%) of 160MHz (2.36-2.52GHz), 160MHz (3.48-3.64GHz) and 520MHz (5.54- 6.06GHz). The absorptions at the center frequency of each band (i.e. 2.45, 3.55 and 5.78GHz) are also found feasible at 97.6%, 85.2% and 96.0%, respectively. From the study, the proposed absorber is applicable for a fairly wide-Angle of wave incidence and suitable for a number of applications in the specified bands. The main advantages of the proposed absorber are thin, simple and low-cost structure, which can be very useful for various applications in WLAN and WiMAX bands.
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    Design of triple-band antenna using S-shaped patch fed by cross strip line for WLAN and WiMAX applications
    (2015-09-01)
    Chawanonphithak, Yuktitath
    ;
    Phongcharoenpanich, Chuwong
    This paper presents a simple triple-band S-shaped patch antenna fed by a cross strip line for both WLAN and WiMAX applications. It is operated at the triple bands of 2.4 and 5.2 GHz for WLAN and 3.5 GHz for WiMAX. The antenna, designed on an FR4 substrate with a thickness of 1.6 mm and relative permittivity of 4.4, is fed by a 50-Ω microstrip line, and is of size 25 × 35 mm. The simulated and measured results of |S<inf>11</inf>|, gains, and radiation patterns are presented. The measured results show that the triple-band antenna achieves a broad operating bandwidth of 2.36-2.54, 3.27-3.69, and 5.16-5.48 GHz for a 10-dB return loss (i.e. |S<inf>11</inf>|<-10 dB). The gains of the antenna measured at 2.4, 3.5, and 5.2 GHz frequencies are 1.87, 1.95, and 3.82, respectively. The radiation pattern of the antenna is omnidirectional.
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    Signal processing of WiMAX physical layer based on low-density parity-check codes
    (2014-12-16)
    Benjangkaprasert, Chawalit
    ;
    Inchan, Torpong
    WiMAX technology supports very high data rate, high capacity and high quality in mobile broadband wireless access system. The performance of the WiMAX system can be enhanced by incorporating a better channel coding technique. This paper presents the excellent performance channel coding known as low-density parity check (LDPC) codes which is a part of WiMAX system. A modified array code parity check matrix for LDPC encoder is used and the message passing (MP) algorithm for LDPC decoder is used, respectively. Both systems are modulated by the basic standard modulation scheme. The computer simulation results confirm that the bit error rate (BER) performance of the WiMAX system that incorporate with the powerful LDPC coding technique has been improved over the conventional standard WiMAX system. However, the computational complexity of the proposed WiMAX system is higher than the previous one.
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    Multi wavelength generated by PANDA ring resonator for multi user DWDM WiMAX network
    (2014-01-01)
    Songmuang, S.
    ;
    Sappajak, S.
    ;
    Thammawongsa, N.
    ;
    Pornsuwancharoen, N.
    ;
    Yupapin, P. P.
    This paper proposed a scheme for multi channels THz frequency generation by using a coupled nonlinear resonator device known as PANDA ring. Dipole gold nano-antenna coupled to active plasmonic devices was used at THz for WiMAX network applications. Multiple Dark-Bright soliton conversion control propagating within a modified PANDA ring resonator to generated dense wavelength division multiplexing (DWDM).The system results illustrated multi wavelength Dark-Bright soliton generation and the frequency obtained in multi THz frequency to broadcast the data to transmitter for all receivers. In this approach, the muti THz frequency provides a reliable frequency band for the future planar lightwave circuit (PLCs) based on DWDM optical link with Wi-Fi, WiMAX, Ubiquitous, and many applications. © (2014) Trans Tech Publications, Switzerland.
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    Ultra-wideband slot antenna on flexible substrate for WLAN/WiMAX/UWB Applications
    (2014-01-01)
    Archevapanich, Tuanjai
    ;
    Lertwatechakul, Mayuree
    ;
    Rakluea, Paitoon
    ;
    Anantrasirichai, Noppin
    ;
    Chutchavong, Vanvisa
    An ultra-wideband slot antenna on flexible substrate is designed to support a wide range of wireless communication systems. The antenna is a rectangular slot antenna fed by microstrip line with conductor strip and tuning stub on flexible substrate (Mylar Polyester film). The rectangular slot is etched out from the ground plane with conductor strip in the slot, and the other plane contains a microstrip line with tuning stub. The proposed antenna’s effective frequency range covers overall standard bands of WLAN, WiMAX, and UWB. The antenna was simulated and analyzed by using IE3D Zeland software [1]. And the simulation results presents the characteristics of the antenna in terms of bandwidth return loss, VSWR, and radiation patterns.
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    Analytical study of signal processing on WiMAX system via physical layer simulation build on IEEE802.16 standard
    (2012-12-01)
    Inchan, T.
    ;
    Benjangkaprasert, C.
    IEEE802.16, which known as WiMAX technology, that is a promised broadband wireless technology that promises high-speed data services up to the costumer end. The aim of this paper is the study of the performance evaluation of a WiMAX system, which building physical layer block models, build on IEEE802.16 standards. The model simulate for study and analysis in the effects of difference transmission channel condition consist of AWGN channel and Rician fading channel concatenated. © 2012 IEEE.
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    Development of a WiMAX processor by using a CPLD
    (2010-12-01)
    Sato, Tomoaki
    ;
    Moungnoul, Phichet
    ;
    Fukase, Masa Aki
    WiMAX (Worldwide Interoperability for Microwave Access) is one of the standards for high-speed wireless communications. The development cycle of a WiMAX processor is short because a transmission rate of a WiMAX system improves gradually. To keep using it even when the speed improves, there is a method of development that uses a processor that can be a reconfiguration of a circuits. In this paper, a mobile WiMAX processor by using a CPLD (Complex Programmable Logic Device) is proposed. Because wave-pipeline technique is used, the problem of processing speed is canceled. The authors evaluate wave-pipelined circuits which WiMAX processor needs on a CPLD. It is made clear that wave-pipeline technique is effective in the circuits on the CPLD.