Archives

2017

Vol 2, No 2 (2017): Channel Estimation of Orthogonal Frequency Division Multiplexing (OFDM) System

Authors: Umesha G B, M N Shanmukha Swamy

Abstract: Orthogonal frequency division multiplexing (OFDM) provides an effective and low complexity means of eliminating inter symbol interference for transmission over frequency selective fading channels. This technique has received a lot of interest in mobile communication research as the radio channel is usually frequency selective and time variant. In OFDM system modulation may be coherent or differential Channel state information (CSI) is required for the OFDM receiver to perform coherent detection or diversity combining if multiple transmit and receive antennas are deployed. In practice CSI can be reliably estimated at the receiver by transmitting pilots along with data symbols. Pilot symbol assisted channel estimation is especially attractive for wireless links where the channel is time-varying. In this research work, we investigate and compare various efficient pilot based channel estimation schemes for OFDM systems.

Vol 2, No 2 (2017): Generation of Different Amplitude Modulated Signals using MATLAB Simulink

Authors: Ashwini B N, Shruthi S Prabhu, Abhilash G 

Abstract: In this paper, implementation of amplitude modulation techniques is presented. In terrestrial television broadcasting, vestigial side modulation (VSB) is used to transmit video signal. SSB modulation is used in frequency modulation to improve the bandwidth. Compared to all amplitude modulation techniques, VSB have tradeoff between power and bandwidth. The different amplitude modulated signals are implemented in Matlab simulink and spectrums are observed.

Vol 2, No 2 (2017): Propeller Display Based on Persistence of Vision Using RF Transceivers

Authors: G.Manjula, Shyamala C

Abstract: In current era, energy is the main factor in designing all the applications, maximum and efficient use of the energy is very important. Conventional methods of displaying images and text in public are using LCD display and dot-matrix LED board. Propeller LED display is a device that project an image or text with least number of LED’s that appear as if they are floating in the air. The floating image is received because of human eye limitation, i.e. because of an illusionary principle persistence of vision (POV), actually the floating images emerge by synchronizing LED'S blink to form an image at particular time and rate. The implementation for the display is done with an advanced RISC based Harvard microcontroller. This platform brings a newer coding and a different understanding of peripherals. The project also aims to build the newer display to work with modern forms of interfaces. The project can be also be implemented with help of any Android Smartphone/tablet running with higher Android versions as the extension of the current work.

Vol 2, No 1 (2017): Comparison of Different Techniques of PAPR Reduction in OFDM System

Authors: Sahil Hamid, Ruchi Sharma, Mahinder Kumar

Abstract: Orthogonal frequency division multiplexing (OFDM) is a well-organized frequently used multicarrier modulation method for high speed data communication over multipath fading channels. OFDM modulation technique offer many benefits for multicarrier transmission at high information rates. One of the major limitations of OFDM is high peak to-average power ratio (PAPR) of the transmitted signal that badly influences the complexity of high power amplifier. Various promising procedures have been anticipated and implemented to decrease PAPR of OFDM signal at the outlay of transmitted signal power, bit error rate (BER), complexity and so on. In this paper, Clipping and Filtering, Selective Mapping (SLM), Partial Transmits Sequence (PTS), tone insertion and tone reservation techniques are discussed briefly for PAPR reduction OFDM signal at transmitter. A brief comparison of these PAPR reduction techniques is done in light of CCDF and BER.

Vol 2, No 1 (2017): PLC Controlled Two Axis Automatic Solar Tracking System

Author: Md. Anwarul Abedin

Abstract: Use of solar energy is rapidly advancing as an important means of renewable energy resource. Solar tracking enables more solar energy to be generated because the solar panel is able to maintain a perpendicular profile to the sun’s rays. The dual axis solar photovoltaic panel is characterized by the capability to move in horizontal and vertical directions. The control circuit for the solar tracker is based on LS Programmable Logic Controller (PLC). The mechanical design consists of rotary joints and two DC motors. This tracking system makes the solar photovoltaic panel more efficient by keeping the panel’s face perpendicular to the sun and therefore extracts maximum solar energy resulting into increased overall efficiency. It detects the sunlight through the LDRs as a sensor and then actuates the DC motors using PLC to position the solar panel where it can receive maximum sunlight. This research study shows that if the movable structures are used in a large scale in a solar power plant, a significant amount (nearly 40%) of more energy can be produced using the same arrays. The proposed control has the capability to be installed in different regions with minor modifications.


2016

Vol 1, No 1 (2016): A Comparative Study of EMD and EEMD Based Adaptive Thresholding Method for Speech Enhancement

Authors: Nayana C.G, Shruthi S Prabhu, Parameshachari B.D, Rudresh M.D

Abstract: From last few decades many frequency domain speech denoising algorithms have been proposed for the speech enhancement. Purpose of speech enhancement is to improve the quality of speech which is most prominent in telecommunication applications. The main objective of this paper is to develop a time domain speech denoising algorithm which offers superior performance compared to previous approaches. This paper demonstrates the time domain methods of speech denoising called Empirical Mode Decomposition (EMD). EMD decomposes speech signal corrupted by noise into band limiting signals called intrinsic mode functions. Each of the IMF is thresholded directly; on the other hand the IMF’s are divided into frames then thresholded for noise removal. One of the drawbacks of EMD is mode mixing, which is often a consequence of signal intermittency. The mode mixing can be elevated by Ensemble Empirical Mode Decomposition (EEMD) which is the modification of EMD. The performance of the EMD and EEMD algorithm are evaluated for wide range of input SNR’s and good efficiency is derived for EEMD based framed thresholding for speech enhancement.

Vol 1, No 1 (2016): RFID Integration with Wireless Sensor Networks

Authors: Dr. A. Narmada, Dr. P. Sudhakara Rao

Abstract: Radio Frequency Identification (RFID) and Wireless Sensor Network (WSN) are two important wireless technologies that have wide variety of applications and provide limitless future potentials. However, RFID and sensor networks almost are under development in parallel way. Integration of RFID and wireless sensor networks attracts little attention from research community. This paper first presents a brief introduction on RFID, and then investigates recent research works, new products/patents and applications that integrate RFID with sensor networks. Four types of integration are discussed. They are integrating tags with sensors, integrating tags with wireless sensor nodes, integrating readers with wireless sensor nodes and wireless devices, and mix of RFID and sensors. New challenges and future works are discussed in the end.

Vol 1, No 1 (2016): Evaluation of Position Tracking System Using GPS Technology

Authors: Zafar Ansari, Sneha Nagar

Abstract: In this paper we introduce the Position tracking system by using wireless sensor technology. In This paper present the development of the position tracking system's hardware prototype. Specifically, the system will utilize GPS to obtain a object's coordinate and transmit it using GSM modem to the user's phone through the mobile network.[1] an position tracking systems in real time has playing key role in present day scenario. Tracking System consists of a two units: one is Tracker Unit this unit senses the position and stores that information in the database and uses this data to locate the position of the vehicle on the Google maps. This paper a new technique proposed that interfaces database (vehicle information) with the Google maps. That map indicates the position of vehicle and alerts the person who is monitoring the information.[8]

Vol 1, No 1 (2016): ARIMA Model for Forecasting Telecommunications Traffic

Authors: Nilesh Subhash Nalawade, Anjuman Akbar Mulani

Abstract: According to International Telecommunication Union (ITU), forecasting of telecommunication data is found to be difficult due to uncertainty involved and the continuous growth of data in telecommunication markets as it helps them in planning and determining their networks. So, there is a need of a good forecasting model to predict the future. In this paper, Autoregressive Integrated Moving Average model is utilized for forecasting telecommunication data. This model adaptively uses auto regression, moving average or combined together if required. The major steps involved in the ARIMA model is identification, estimation and forecasting. The adaptive ARIMA model is then applied to M3-Competition Data to do forecasting of telecommunication data. The performance of the model is found out using the evaluation metrics such as Sum of Squared Regression, Root Mean Square Error, Mean Absolute Deviation, Mean Absolute Percentage Error and Maximum Absolute Error. The results proved that the ARIMA models provide 7.6% improvement than the neural network method in forecasting performance.


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