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This work studies the relationship between laser irradiance and pulse frequency effect on plasma features of the TiO₂. This target was irradiated by a Q-switched nanosecond Nd: YAG laser with the first harmonic generation (FHG) wavelength (1064nm), laser energy 500mJ, and pulse frequency ranging from 6Hz to 10Hz at atmospheric pressure. The Boltzmann plot and the Stark broadening methods calculated the plasma parameters ($T_e$ and $n_e)$. The findings were examined in light of the previously published experiments and theories, and it was discovered that they agreed with the hypothesis of the local thermodynamic equilibrium (LTE); on the other hand, research was conducted on the other basic plasma properties such as the Debye length (${\lambda }_D$), the Debye sphere ($N_D$), and the plasma frequency (${\omega }_P$). We observed that all plasma parameters are influenced by pulse frequency. The results clarify the linear change in electron temperature at increasing pulse frequency for TiO₂ plasma. In contrast, the broadening of the line profiles related to electron density was evident with pulse frequency, causing an increase in electron density.

A compact low-cost metamaterial circular monopole antenna for LTE applications is presented here. This paper addresses an asymmetric circular split-ring radiator for 2.6GHz (LTE-7 band), 3.5GHz (LTE-22 band). The design here employs split rings with varying split gaps in the consecutive ring layers of the radiating element which helped in achieving better impedance matching for obtaining multiband operation. The work presented here demonstrates the feasibility of achieving double negative material property, without loading the SRR’s separately in the system. The antenna was modeled using a 1.6mm thick FR-4 lossy material. The simulated results were compared with measured results and found to be in good agreement with each other. Employing asymmetric split ring as radiator helped in achieving 29% of size reduction in the patch layer. The modified split-ring radiator achieved directional radiation pattern and minimum side-lobe levels with a peak gain of 1.29 and 0.204dB at the lower band and upper band, respectively. The compact dimension $45\times 40{\text{mm}}^2$ of the radiating system makes it suitable for LTE-WLAN/Wi-Max applications.

Laser ablation of sintered SiO₂:TiO₂ targets using Nd:YAG lasers at fundamental (1064nm) harmonic generation in the air has been studied using optical emission spectroscopy. Exploring the spatial fluctuations in electron temperature ($T_e$) and electron density ($n_e$), there is a discussion of how laser energy affects electron temperature ($T_e$) and electron density ($n_e$). Laser energy has also been shown to affect the intensity and velocity of neutral and ion species. Using existing data and theory, the findings were confirmed following the local thermodynamic equilibrium (LTE) hypothesis. Plasma properties such as Debye length (${\lambda }_d$), ($N_d$) and plasma frequency ($w_p$) were also studied in this study. Using a laser, we found that all plasma parameters were affected. In addition, the calculated inverse Bremsstrahlung absorption coefficients (${\alpha }_{IB}$) were altered.

In this paper, a 1 mm × 1 mm fully integrated wideband dual-stage power amplifier (PA) for long-term evolution (LTE) band 1 (1920–1980 MHz) is presented. Fabricated in a 2 μm InGaP/GaAs hetero-junction bipolar transistor (HBT) process, the operating gain is observed to be 31.3 dB. The PA meets the minimum adjacent channel leakage ratio (ACLR) requirement of -30 dBc for LTE with 20 MHz wide channel bandwidth up to an output power of 30 dBm with the aid of a novel dual stage linearizer. Biased at low quiescent current of less than 100 mA with a headroom consumption of 3.5 V, the power added efficiency (PAE) is observed to be 38.29% at 30 dBm. With this high linear output power, the stringent requirement of antenna path loss is nullified. PA serves to be the first reported work to achieve 30 dBm linear output power at supply voltage of 3.5 V.

Internet protocol (IP)-based mobile systems are ushering new and faster technologies in wireless mobile networking. Therefore, the expectations from these network services with respect to data transfer rate and quality of service (QoS) are high. As such, meeting these requirements is the recent trend in modern wireless technologies. An important aspect regarding such improvements is the modification of handoff schemes between different networks. In this paper, we are focusing on the recent trends based on seamless handoff scheme in heterogeneous networks such as worldwide interoperability for microwave access (WiMAX) and long term evolution (LTE). The development of the session initiation protocol (SIP) Prior-INVITE scheme is an improvement on the earlier used SIP Re-INVITE method, which comes a long way in decreasing the average handoff delay. The performance analysis using software simulation on account of various parameters, such as handoff delay, cost of signaling and packet loss rate are accomplished in this work. The performance analysis demonstrates that the proposed scheme outperforms the ordinary cross-layer scheme and noncross-layer scheme in a vertical handover scenario.

With the new age of technology and the release of the Internet of Things (IoT) revolution, there is a need to connect a wide range of devices with varying throughput and performance requirements. In this paper, a digital transmitter of NarrowBand Internet of Things (NB-IoT) is proposed targeting very low power and delay-insensitive IoT applications with low throughput requirements. NB-IoT is a new cellular technology introduced by 3GPP in release 13 to provide wide-area coverage for the IoT. The low-cost receivers for such devices should have very low complexity, consume low power and hence run for several years. In this paper, the implementation of the data path chain of digital uplink transmitter is presented. The standard specifications are studied carefully to determine the required design parameters for each block. And the design is synthesized in UMC 130-nm technology.

As single-carrier frequency division multiple access (SC-FDMA) is used in long-term evolution (LTE) uplink communications, high peak-to-average power ratio (PAPR) increases power consumption in mobile devices. It is severe when localized subcarrier mapping is used with higher-order modulations. Companding is an attractive technique that offers a tradeoff between PAPR and bit error rate (BER) performances. This paper proposes an exponential companding technique that uses two companding levels based on a threshold, to reduce PAPR in SC-FDMA systems. It does not increase the average power level of transmitted signal and maintains the BER level without significant degradation from the original system. The proposed scheme has three parameters that can be adjusted for a tradeoff between PAPR, BER, and power spectral density (PSD) performances. Hence it offers more flexibility than the conventional exponential companding scheme. We also present scatter plots to find the optimum threshold value and companding levels. Finally, we verify the proposed technique considering a real-time indoor channel by using a wireless open-access research platform (WARP).

MIMO is a type of antenna technology which utilizes multiple antennas to separate signals traveling in various paths as a result of reflections, etc., to be separated and their ability utilized to enhance the throughput of data and the signal to noise ratio which in return enhances the performance of the system. For providing enhanced signal performance and enhanced data rates, MIMO is utilized within LTE. When the quantities of antennas are increased, there is increase in the probability that deep fading is experienced by at least some antennas, which affects the overall efficiency of the MIMO system. To handle these issues, a reliable technique has been presented that involves selection of antenna subset. The proposed technique incorporates combination of SBO and PSO for antenna selection. Antenna selection’s main concept is to utilize a bounded quantity of analog chains that are adaptively switched to subset of the available antennas capable of preserving the selection diversity gains and also can minimize the quantity of radio frequency chains needed. The maximum channel capacity of the channel has been considered as the objective function for selecting optimal antennas. The comparison of the proposed approach’s performance and the existing approaches’ performance is done. From the simulation result, it has been shown that the presented approach’s performance has been better than the performance of the existing approaches in terms of BER, energy efficiency, spectral efficiency and optimal transmit power.