Abstract Higher the data rates and spectrum efficiency of wireless mobile communications have been significantly improved over the last decade, such as 3GPP Long-Term Evolution (LTE) and terrestrial digital TV broadcasting which are sophisticatedly developed using OFDM. Orthogonal frequency division multiplexing (OFDM) is a modulation technique that achieves high data rates, increased bandwidth efficiency and robustness in multipath environments. However, OFDM has some disadvantages, such... Higher the data rates and spectrum efficiency of wireless mobile communications have been significantly improved over the last decade, such as 3GPP Long-Term Evolution (LTE) and terrestrial digital TV broadcasting which are sophisticatedly developed using OFDM. Orthogonal frequency division multiplexing (OFDM) is a modulation technique that achieves high data rates, increased bandwidth efficiency and robustness in multipath environments. However, OFDM has some disadvantages, such as sensitivity to channel fading, large peak to average ratio and sensitivity to frequency offset. The latter causes inter carrier interference (ICI) and a reduction in the amplitude of the desired subcarrier which results in loss of orthogonality. In this paper, the effects of frequency offset are studied in terms of loss of orthogonality. The main goals of this paper is to understand the effects of frequency offset on OFDM systems and to present frequency offset estimation techniques so that we can correct for their effects. The performance of each technique is compared under various conditions. The performance of the estimators is presented in terms of the mean square error (MSE) and Signals to noise ratio (SNR). In this paper, we investigate carrier frequency synchronization in the downlink of 3GPP Long Term Evolution (LTE). A complete carrier frequency offset estimation and compensation scheme based on standardized synchronization signals and reference symbols is presented. The estimation performance in terms of mean square error is derived analytically and compared to simulation results. Read More Read Less

Abstract The air traffic controllers of the El Alto airport must give to the landing and taking off aircrafts, necessary information such as the visibility of the runway, the wind speed and direction, cloud cover, temperature, pressure, etc. This information called Meteorological Terminal Aviation Routine Weather Report (METAR) is essential for taking decision respect to the landing procedure. At aerodromes with a considerable level... The air traffic controllers of the El Alto airport must give to the landing and taking off aircrafts, necessary information such as the visibility of the runway, the wind speed and direction, cloud cover, temperature, pressure, etc. This information called Meteorological Terminal Aviation Routine Weather Report (METAR) is essential for taking decision respect to the landing procedure. At aerodromes with a considerable level of traffic, the METAR issue has become a problem, may cause congestion of the communication frequency, this has caused aviation incidents; otherwise the operations are delayed and are not as smooth and efficient on the airfield. The air traffic controller is responsible for issuing the current weather conditions, for this task, the manager of the garden weather must copy the collected data and make a report to communicate the weather condition at the moment, but he takes the report every hour. In summary, there are two main problems; the first is that one provide weather reports that are not of the moment, which can produce aircraft incidents, and finally there is a congested communication frequency, for this reason, the operations are not optimal and fluid. The aim of this work is to implement the ATIS (Automatic Terminal Information System) for El Alto airport. Read More Read Less

Abstract The performance of cellular networks will experience a considerable improvement by the use of newtechnologies such as distributed antenna systems (DASs), multi-cell cooperation (MCC), and cognitive radio (CR).However, several issues remain open in the system-level evaluation, radio resource management (RRM), and particularlyin the design of billing/licensing schemes for these types of system. This paper proposes a system-level simulator(SLS) that will help us address these... The performance of cellular networks will experience a considerable improvement by the use of newtechnologies such as distributed antenna systems (DASs), multi-cell cooperation (MCC), and cognitive radio (CR).However, several issues remain open in the system-level evaluation, radio resource management (RRM), and particularlyin the design of billing/licensing schemes for these types of system. This paper proposes a system-level simulator(SLS) that will help us address these issues. An advanced RRM solution is also proposed for a multi-cell DAS in adense urban Manhattan scenario with two levels of cooperation: inside the cell (intra-cell) to coordinate the transmissionof distributed nodes controlled by the base station of the cell, and between cells of a cluster (inter-cell) toadapt cell transmissions according to updated intercell interference measurements. The RRM solution blends networkand financial metrics using the theory of multi-objective and financial portfolio optimization. In this paper each network/spectrum resource is considered as a financial asset whose allocation has to be optimized based on economic metrics such as return and risk (i.e., variation of the return). The core of the intra-cell RRM algorithm is based on an iterative weighted least squares (WLS) optimization scheme where power levels and beam-forming vectors are jointlydesigned to comply with a target instantaneous SINR (signal-to-interference-plus-noise ratio) threshold for each transmission.This instantaneous SINR threshold ensures the transmission of the selected modulation and coding scheme(MCS) with a given value of BLER (block error rate) and spectral efficiency. The WLS scheme allows for a smoothintegration of scheduling and adaptive modulation and coding (AMC) schemes with the underlying space division multiplexing(SDM) physical layer. Convergence speed is improved by reusing the outcome of previous WLS iterations.The weight coefficients of the WLS optimization contain network metrics such as queue length and fairness, as well aseconomic metrics such as return and risk. This process is complemented with a multi-objective and financial portfoliooptimization stage for joint spectrum selection and resource (chunk) allocation that attempts to maximize return and minimize risk. Cells within a cluster exchange the results of their optimization processes for purposes of rejectinginter-cell interference, thereby achieving MCC. All resource allocation schemes use an imperfect copy of channel and queueing state information, which is the result of inaccurate measurements, imperfect feedback, or sensing errors. Read More Read Less

Abstract This work focuses on the design of a novel FPGA architecture based on memristor-transistor hybrid approach. A lot of research has been carried out in the field of FPGA that has focused on decreasing the size and power consumption of FPGAs. However, still FPGAs are larger in area, slower in speed and more power consuming. In this work, basic building blocks like MUX,... This work focuses on the design of a novel FPGA architecture based on memristor-transistor hybrid approach. A lot of research has been carried out in the field of FPGA that has focused on decreasing the size and power consumption of FPGAs. However, still FPGAs are larger in area, slower in speed and more power consuming. In this work, basic building blocks like MUX, NOR gate, D flip flop, NOT gate and buffer are designed and implemented using memristor-transistor hybrid approach. These basic building blocks are combined to form Configurable Logic Blocks (CLBs), Switch Boxes (SBs) and Connection Boxes (CBs) of FPGA. Proposed hybrid basic building blocks of FPGA are smaller in size and lower in power consumption as compared to the conventional transistor-only building blocks. For experimental purpose, first we compare the area and power of conventional and proposed basic building blocks and achieve the average area and power efficiency of 30% and 60% respectively. Similarly, the area gain of a 2 input single tile based on proposed basic building block is 39%. Then, we also explore the overall area of memristortransistor hybrid FPGA architecture for sixteen largest MCNC benchmarks and present the results. Read More Read Less