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Walsh-Hadamard-transform-based SC-FDMA system using WARP hardware
Kondamuri, Shri Ramtej,Anuradha, Sundru Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.2
Single-carrier frequency division multiple access (SC-FDMA) is currently being used in long-term evolution uplink communications owing to its low peak-to-average power ratio (PAPR). This study proposes a new transceiver design for an SC-FDMA system based on Walsh-Hadamard transform (WHT). The proposed WHT-based SC-FDMA system has low-PAPR and better bit-error rate (BER) performance compared with the conventional SC-FDMA system. The WHT-based SC-FDMA transmitter has the same complexity as that of discrete Fourier transform (DFT)-based transmitter, while the receiver's complexity is higher than that of the DFT-based receiver. The exponential companding technique is used to reduce its PAPR without degrading its BER. Moreover, the performances of different ordered WHT systems have been studied in additive white Gaussian noise and multipath fading environments. The proposed system has been verified experimentally by considering a real-time channel with the help of wireless open-access research platform hardware. The supremacy of the proposed transceiver is demonstrated based on simulated and experimental results.
SOME RESULTS INVOLVING THE MULTIPLE H FUNCTION
Mathur, B.L.,Krishna, Shri Department of Mathematics 1978 Kyungpook mathematical journal Vol.18 No.2
The object of the present paper is to obtain certain results involving the H function of several complex variables. An integral involving the generalized Whittaker functions and the multiple H function has been evaluated and this result has been further utilized in finding out an expansion formula for the multiple H function in terms of the Laguerre polynomials. Some particular cases of interest have also been indicated.
Sintering and Oxidation of GdB<sub>4</sub> Synthesized by B<sub>4</sub>C Reduction Method
Sonber, Jitendra Kumar,Murthy, Tammana Shri Ram Chandra,Sairam, Kannan,Kain, Vivekanand The Korean Ceramic Society 2017 한국세라믹학회지 Vol.54 No.2
Gadolinium tetraboride ($GdB_4$) was synthesized by reduction of $Gd_2O_3$ using boron carbide in presence of carbon. Effect of temperature on product quality was investigated. Pure $GdB_4$ powder was obtained in vacuum at $1500^{\circ}C$. Pressureless sintering experiments revealed that sintering takes place only above $1600^{\circ}C$. A maximum density of 77.1% of the theoretical value was obtained at $1800^{\circ}C$ by pressureless sintering. Hot pressing resulted in 95.5% of theoretical density at the lower temperature of $1700^{\circ}C$ under 35 MPa pressure. Hardness and fracture toughness of dense $GdB_4$ were measured and found to be 21.4 GPa and $2.3MPa{\cdot}m^{1/2}$, respectively. After exposure to air at $900^{\circ}C$, the formation of a porous and non-protective oxide layer was observed.