The weakness of the orthogonal freuency division multiplexing (OFDM) system is susceptible to the existence of carrier frequency offset (CFO) which causes the emergence of inter carrier interference (ICI) which causes a degradation of performance OFDM systems. This study aims to apply the suggested rectangular (REC) pulse and improved sinc-power (ISP) pulse shaping methods on OFDM system and determines ICI reduction with the effects of CFO over flat fading Rayleigh channels. The performance of each pulse shaping method is evaluated and compared based on parameter ICI power vs. normalized frequency offset, signal to interference ratio (SIR) vs. normalized frequency offset and bit error rate (BER) vs. energy bit per noise (Eb/No). The simulation result in terms of BER vs. Eb/No indicated that REC and ISP pulse shaping has better performance dealing with ICI reduction compared to OFDM system no applied pulse shaping. In addition, the ISP is able to mitigate ICI better than REC.
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Enhancing the BER and ACLR for the HPA Using Pre-Distortion TechniqueIJECEIAES
Power amplifiers are key components in wireless transceivers. Their function is to amplify signal and generate the required Radio Frequency (RF) power that allows to transmit the signal over an appropriate range. The Orthogonal Frequency Division Multiplexing (OFDM) systems are highly sensitive to nonlinear distortion introduced by High Power Amplifier (HPA). The HPA nonlinearity causes in-band and out-of-band distortions. The linearization techniques are used to compensate the nonlinear effects of the high power amplifier. These techniques correct the distortion effects resulting from nonlinearities in the transmitted signal. Many linearization techniques have been developed to improve power amplifier linearity and to decrease both Bit Error Rate (BER) and Adjacent Channel Leakage Ratio (ACLR). This work is set to run the high power amplifier in the nonlinear region. It is also attempting to analyze the resulting signal in terms of the BER and ACLR, next employs pre-distortion linearization techniques to reduce the distortion introduced in this region. According to Digital Video Broadcasting-Terrestrial (DVB-T) standard the linearization techniques, circuit and the OFDM transmitter and receiver is designed and implemented through using computer simulation of AWR Design Environment.
Performance Evaluation and Simulation of OFDM in Optical Communication SystemsIJERA Editor
Orthogonal Frequency Division Multiplexing (OFDM) is of prime importance nowadays in long haul
communication networks because of its higher spectral efficiency, immunity to multipath fading and its
resilience to interference. Optical Orthogonal Frequency Division Multiplexing is considered as a promising
technology to satisfy the increased demand for bandwidth in broadband services. It is of two types based on the
detection techniques employed. They are direct detection and coherent detection. In direct detection OFDM, a
photodiode is used while in the latter the principle of optical mixing is utilized. This paper investigates the
architecture of single channel and four channel direct detection and coherent detection optical OFDM systems
and carries out performance analysis based on bit error rate and Q-factor. In the case of single channels, a date
rate of 10 Gbps is achieved while in 4 channel systems a data rate of 40 Gbps is achieved. Coherent Optical
OFDM (CO-OFDM) is the next generation technology for the optical communications, since it integrates the
advantages of both coherent systems and OFDM systems.
Received Power performance in downlink architecture of Radio-over-Fiber Trans...IOSR Journals
Abstract : The In this paper, we studied the RoF system and analyzed the received power performance in downlink architecture of RoF system. The RoF system employs a Mach–Zehnder modulator (MZM) and a phase shifter to externally generate an optical single sideband (OSSB) signal since the OSSB signal is tolerable for power degradation due to a chromatic fiber-dispersion effect. The received power performance is analyzed by calculating a factor called Power Penalty. It is shown that Power penalty is increased exponentially as the differential delay increased with the distance due to chromatic dispersion with the change in laser linewidth (𝛾𝑅𝐹) from 10MHz to 1000MHz. The results are calculated for various transmission distances (𝐿𝐹𝐼𝐵𝐸𝑅) 1km to 40km for optical distances. The frequency of laser taken is 30-GHz RF carrier (𝑓𝑅𝐹) and wavelength 1550-nm laser (λ) with zero line width, fiber dispersion parameter (D) 17 ps/nm·km.
Keywords: Chromatic dispersion, DEMZM, Laser line width, Power penalty and Received power.
Performance and interference analysis of 802.11 g wireless networkijwmn
This paper mainly presents Access Point s’ (APs’) p
erformance and co-channel, adjacent channel
interference according to 802.11g standard. Firstly
, our study illustrates the performance of one AP,
including its coverage performance, load-carrying p
roperties and fairness. Next we propose the details
about co-channel, adjacent channel interference whi
ch should be paid attention to in deploying network
services. Then, performance analyses are evaluated
by simulation and real test for a dense wireless
network. Our contribution is that the co-channel, a
djacent channel interference analysis, the simulati
on
and test results can be the basis offered to networ
k operators
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
International Journal of Computational Engineering Research (IJCER) is dedicated to protecting personal information and will make every reasonable effort to handle collected information appropriately. All information collected, as well as related requests, will be handled as carefully and efficiently as possible in accordance with IJCER standards for integrity and objectivity.
Enhancing the BER and ACLR for the HPA Using Pre-Distortion TechniqueIJECEIAES
Power amplifiers are key components in wireless transceivers. Their function is to amplify signal and generate the required Radio Frequency (RF) power that allows to transmit the signal over an appropriate range. The Orthogonal Frequency Division Multiplexing (OFDM) systems are highly sensitive to nonlinear distortion introduced by High Power Amplifier (HPA). The HPA nonlinearity causes in-band and out-of-band distortions. The linearization techniques are used to compensate the nonlinear effects of the high power amplifier. These techniques correct the distortion effects resulting from nonlinearities in the transmitted signal. Many linearization techniques have been developed to improve power amplifier linearity and to decrease both Bit Error Rate (BER) and Adjacent Channel Leakage Ratio (ACLR). This work is set to run the high power amplifier in the nonlinear region. It is also attempting to analyze the resulting signal in terms of the BER and ACLR, next employs pre-distortion linearization techniques to reduce the distortion introduced in this region. According to Digital Video Broadcasting-Terrestrial (DVB-T) standard the linearization techniques, circuit and the OFDM transmitter and receiver is designed and implemented through using computer simulation of AWR Design Environment.
Performance Evaluation and Simulation of OFDM in Optical Communication SystemsIJERA Editor
Orthogonal Frequency Division Multiplexing (OFDM) is of prime importance nowadays in long haul
communication networks because of its higher spectral efficiency, immunity to multipath fading and its
resilience to interference. Optical Orthogonal Frequency Division Multiplexing is considered as a promising
technology to satisfy the increased demand for bandwidth in broadband services. It is of two types based on the
detection techniques employed. They are direct detection and coherent detection. In direct detection OFDM, a
photodiode is used while in the latter the principle of optical mixing is utilized. This paper investigates the
architecture of single channel and four channel direct detection and coherent detection optical OFDM systems
and carries out performance analysis based on bit error rate and Q-factor. In the case of single channels, a date
rate of 10 Gbps is achieved while in 4 channel systems a data rate of 40 Gbps is achieved. Coherent Optical
OFDM (CO-OFDM) is the next generation technology for the optical communications, since it integrates the
advantages of both coherent systems and OFDM systems.
Received Power performance in downlink architecture of Radio-over-Fiber Trans...IOSR Journals
Abstract : The In this paper, we studied the RoF system and analyzed the received power performance in downlink architecture of RoF system. The RoF system employs a Mach–Zehnder modulator (MZM) and a phase shifter to externally generate an optical single sideband (OSSB) signal since the OSSB signal is tolerable for power degradation due to a chromatic fiber-dispersion effect. The received power performance is analyzed by calculating a factor called Power Penalty. It is shown that Power penalty is increased exponentially as the differential delay increased with the distance due to chromatic dispersion with the change in laser linewidth (𝛾𝑅𝐹) from 10MHz to 1000MHz. The results are calculated for various transmission distances (𝐿𝐹𝐼𝐵𝐸𝑅) 1km to 40km for optical distances. The frequency of laser taken is 30-GHz RF carrier (𝑓𝑅𝐹) and wavelength 1550-nm laser (λ) with zero line width, fiber dispersion parameter (D) 17 ps/nm·km.
Keywords: Chromatic dispersion, DEMZM, Laser line width, Power penalty and Received power.
Performance and interference analysis of 802.11 g wireless networkijwmn
This paper mainly presents Access Point s’ (APs’) p
erformance and co-channel, adjacent channel
interference according to 802.11g standard. Firstly
, our study illustrates the performance of one AP,
including its coverage performance, load-carrying p
roperties and fairness. Next we propose the details
about co-channel, adjacent channel interference whi
ch should be paid attention to in deploying network
services. Then, performance analyses are evaluated
by simulation and real test for a dense wireless
network. Our contribution is that the co-channel, a
djacent channel interference analysis, the simulati
on
and test results can be the basis offered to networ
k operators
The International Journal of Engineering and Science (The IJES)theijes
The International Journal of Engineering & Science is aimed at providing a platform for researchers, engineers, scientists, or educators to publish their original research results, to exchange new ideas, to disseminate information in innovative designs, engineering experiences and technological skills. It is also the Journal's objective to promote engineering and technology education. All papers submitted to the Journal will be blind peer-reviewed. Only original articles will be published.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A New Dual Band Printed Metamaterial Antenna for RFID Reader Applications IJECEIAES
In this paper, we present a new dual band metamaterial printed antenna for radio frequency identification applications. The proposed antenna consists of two L-shaped slot in the radiating element for dual band operation and a complementary split ring resonator etched from the ground plane for size miniaturization. This antenna is designed and optimized by CST microwave studio on FR-4 substrate with thickness of 1.6 mm, dielectric constant of 4.4 and tangent loss of 0.025. A microstrip line with characteristic impedance of 50 ohms is used to feed this antenna. A prototype of the proposed antenna is fabricated to validate the simulation results. The measured and simulated results are in good agreement.
Comparative Analysis of Dispersion Compensating Fiber (DCF) and Multiple Opti...rahulmonikasharma
Optical communication when used for long haul communication is characterized by dispersion and nonlinearities. Different techniques are used for the dispersion compensation and nonlinearity mitigation. Two of these techniques are Dispersion Compensating Fiber (DCF) and Optical Phase Conjugation (OPC). In this paper the performance of the system is analyzed by comparing various results at the receiver. A 10Gb/s NRZ signal is launched into a long Single Mode Fiber (SMF). Results in the terms of Q-factor (linear) and BER are observed by varying fiber length. Optical system consisting of one OPC and two OPC is also analyzed for different transmission distance. Simulation results show that, when compared with optical system consisting of one OPC, Q-factor improvement of 3.51 is achieved for the optical system consisting of two OPC. Nonlinearities are mitigated using DCF and OPC and on comparing with DCF, Q-factor improvement of 11.3 is achieved for OPC.
Comparative performance of optical amplifiers: Raman and EDFATELKOMNIKA JOURNAL
The in-line optical signal amplification is often used in optical communication systems to accomplish longer transmission distances and larger capacity. In this proposed paper, the operation of two types of optical amplifiers for 16×10 Gbps wavelength division multiplexing system had been examined by changing transmission distance from 10 to 200 km with a dispersion equals to 16.75 ps/nm/km. The analysis and design of such systems ordinarily includes many signal channels, nonlinear devices, several topologies with many noise sources, is extremely complex and effort-exhaustive. Therefore, theoretical studies with simulation CAD software of systems are become necessity to predict and optimize system performance. The comparison between EDFA and Raman has already explored by many researchers in varying ways in this work and to achieve obove objectives, the OptiSystem software was used to design the proposed fiber optic communications system and to simulate results. Performance for the present system was evaluated for parameters like bit error rate (BER), quality factor (QF), total gain with eye opening factor. It was saw that EDFA provides better results, in the maximal transmission distance 64% better than Raman amplifier, 57.5% for amplification gain and 26.7% for maximum quality factor. As a future study a hybrid amplifier can produce better quality of amplification.
OFDM (Optical Orthogonal Frequency Division Multiplexing) in the optical
domain is an emerging technology for fulfilling increased bit rate demand of real time
sophisticated applications. In this work an optical OFDM system is designed using different
M-ary QAM (Quadrature amplitude Modulation) techniques by varying M to 16, 65, 256.
Performance evaluation has been carried in terms of SNR (Signal to noise ratio) and BER
(bit error rate).In present research OPTSIM and MATLAB has been used as Simulation
tools.
DESIGN AND ANALYSIS OF PHASE-LOCKED LOOP AND PERFORMANCE PARAMETERSIJMEJournal1
In this paper, we are present design and analysis of PLL, which is simulated in CMOS 0.18μm technology.The digital phase locked loop achieves locking within about 100 reference clock cycles. The pure digital
phase locked loop is attractive because it is less sensitive to noise and operating conditions than its analog
counterpart.In this PLL circuit successfully achieved 1.55GHz frequency. Jitter is 1.09ns achieved is very
less. Also achieve low phase noise -98.5827 at 1MHz Frequency
Real Time Implementation of Adaptive Beam former for Phased Array Radar over ...CSCJournals
Mechanical positioners, rotating antennas and large size of early generation radars limited the capability of the radar system to track laterally accelerating targets. Electronic Scanning Array (ESA) such as used in Phased Array Radar (PAR) overcomed these limitations by providing beam agility, good response time, variable scan rates and efficient use of energy. Early PAR systems used analog phase shifting schemes that caused variations and component failures resulting in overall degradation of radar performance. With the advent of new technology and high performance embedded systems, digital beamforming has become powerful enough to perform massive operations required for real time digital beamforming. MATLAB simulation of adaptive beamformer is presented in this paper. Real time implementation of adaptive beamformer over DSP kit (TMS320C6713) was also carried out and results were compared with MATLAB simulations. GUI was also made in MATLAB for viewing results of real time implementation via real time data exchange. Developed system can be used in digital beamforming PAR provided array signals is routed to DSP kit through FPGA interfaced to high speed ADC’s.
PERFORMANCE ASSESSMENT OF MAXIMUM LIKELIHOOD IN THE DETECTION OF CARRIER INTE...IJCNCJournal
Mobile handset carriers are presented as a source of interference to GPS operation in smartphones. The
carriers are presented in terms of their analytical form; block level generation as well as their statistical
distribution model. In addition, we present the analytical form of the received GPS signal corrupted by
carrier interference The Analysis is applied on the chip level in the acquisition engine before stripping the
code or carrier. This expansion will restore the operation of GPS receiver in the presence of carrier
interference. We present an estimate of the amount of improvement that Maximum Likelihood estimation
gives in mitigating carrier interference in smartphones. The amount of improvement is compared to that of
calculations based on measured data processing. The power spectral density of the interference is treated
thoroughly to derive expressions for half of the noise power spectral density.
Design and optimization of a new compact 2.4 GHz-bandpass filter using DGS te...TELKOMNIKA JOURNAL
The objective of this work is the study, the design and the optimization of an innovative structure of a network of coupled copper metal lines deposited on the upper surface of a R04003 type substrate of height 0.813 with a ground deformed by slots (DGS). This structure is designed in an optimal configuration for use in the design of narrowband bandpass filter for wireless communication systems (WLAN), the aim of use the defected ground structure is to remove the unwanted harmonics in the rejection band, the simulation results obtained from this structure using CST software show a very high selectivity of the designed filter, a very low level of losses (less than-0.45 dB) with a size overall size of 43.5x34.3 mm.
Design and optimization of microstrip filtering antenna with modified shaped ...TELKOMNIKA JOURNAL
This paper presents a new compact microstrip filtering antenna with modified shaped slots to improve the impedance bandwidth. The proposed microstrip filtering antenna consists of three parts; the monopole radiating patch antenna, the SIR filter, and the feeding microstrip line. The design structure is achieved on one sided glass epoxy FR-4 substrate with dielectric constant ε_r = 4.4 and thickness of h = 1.6 mm. The design procedures of the proposed filtering antenna starts from the second order Chebyshev low pass filter prototype. The simulation results throughout this article are done by a computer simulation technology (CST) software. The simulated results have been achieved show good performance of S11-parameter and broad side antenna gain on +z-direction. This design has two transmission zeros at 5.4 GHz and 7.7 GHz, and bandwidth (B.W) of about 1.66 GHz so; it is suitable for high speed data communication. This design has good skirt selectivity.
In this paper, UWB technology operating in broad
frequency range of 3.1-10.6 GHz has shown great achievement
for high- speed wireless communications. to satisfy the UWB
system requirements, a band pass filter with a broad pass
band width, low insertion loss, and high stop-band suppression.
UWB band-pass filter (BPF) with wireless local area network
(WLAN) notch at 5.8 GHz and 3-dB fractional bandwidth of
108% using a microstrip structure is presented. Initially a
two transmission pole UWB band pass filter in the frequency
range 3.1-10.6 GHz is achieved by design a parallel-coupled
microstrip line with defective ground plane structure using
GML 1000 substrate with specification: dielectric constant 3.2
and thickness 0.762 mm at centre frequency 6.85 GHz. In this
structure a ë/4 open circuited stub is introduced to achieve the
notch at 5.8 GHz to avoid the interference with WLAN
frequency with lies the desired UWB band. The design
structure was simulated on electromagnetic circuit simulation
software and fabricated by microwave integrated circuit
technique. The measured VNA results show the close
agreement with simulated results.
Comparison of Three Different Cancellation Schemes for Orthogonal Frequency D...ijtsrd
Orthogonal Frequency Division Multiplexing OFDM is an exceptional case of Frequency Division Multiplexing. The dilemma of OFDM is its sensitivity to frequency offset between the transmitted and received carrier frequencies. This frequency offset establishes Inter Carrier Interference ICI Cancellation in the OFDM symbol. ICI reduction methods have been had by OFDM. This research considers three ICI self cancellation SC , maximum likelihood ML estimation, and extended Kalman filter EKF method. These three methods are compared in terms of bit error rate performance, bandwidth efficiency, and computational complexity. For high values of the frequency offset and for higher order modulation schemes, the SC method does not as well as the ML and EKF methods. Simulation results using MATLAB software. Ma Khin Saw | Aye Aye Khine ""Comparison of Three Different Cancellation Schemes for Orthogonal Frequency Division Multiplexing (OFDM) System"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-4 , June 2019, URL: https://www.ijtsrd.com/papers/ijtsrd25182.pdf
Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/25182/comparison-of-three-different-cancellation-schemes-for-orthogonal-frequency-division-multiplexing-ofdm-system/ma-khin-saw
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
A New Dual Band Printed Metamaterial Antenna for RFID Reader Applications IJECEIAES
In this paper, we present a new dual band metamaterial printed antenna for radio frequency identification applications. The proposed antenna consists of two L-shaped slot in the radiating element for dual band operation and a complementary split ring resonator etched from the ground plane for size miniaturization. This antenna is designed and optimized by CST microwave studio on FR-4 substrate with thickness of 1.6 mm, dielectric constant of 4.4 and tangent loss of 0.025. A microstrip line with characteristic impedance of 50 ohms is used to feed this antenna. A prototype of the proposed antenna is fabricated to validate the simulation results. The measured and simulated results are in good agreement.
Comparative Analysis of Dispersion Compensating Fiber (DCF) and Multiple Opti...rahulmonikasharma
Optical communication when used for long haul communication is characterized by dispersion and nonlinearities. Different techniques are used for the dispersion compensation and nonlinearity mitigation. Two of these techniques are Dispersion Compensating Fiber (DCF) and Optical Phase Conjugation (OPC). In this paper the performance of the system is analyzed by comparing various results at the receiver. A 10Gb/s NRZ signal is launched into a long Single Mode Fiber (SMF). Results in the terms of Q-factor (linear) and BER are observed by varying fiber length. Optical system consisting of one OPC and two OPC is also analyzed for different transmission distance. Simulation results show that, when compared with optical system consisting of one OPC, Q-factor improvement of 3.51 is achieved for the optical system consisting of two OPC. Nonlinearities are mitigated using DCF and OPC and on comparing with DCF, Q-factor improvement of 11.3 is achieved for OPC.
Comparative performance of optical amplifiers: Raman and EDFATELKOMNIKA JOURNAL
The in-line optical signal amplification is often used in optical communication systems to accomplish longer transmission distances and larger capacity. In this proposed paper, the operation of two types of optical amplifiers for 16×10 Gbps wavelength division multiplexing system had been examined by changing transmission distance from 10 to 200 km with a dispersion equals to 16.75 ps/nm/km. The analysis and design of such systems ordinarily includes many signal channels, nonlinear devices, several topologies with many noise sources, is extremely complex and effort-exhaustive. Therefore, theoretical studies with simulation CAD software of systems are become necessity to predict and optimize system performance. The comparison between EDFA and Raman has already explored by many researchers in varying ways in this work and to achieve obove objectives, the OptiSystem software was used to design the proposed fiber optic communications system and to simulate results. Performance for the present system was evaluated for parameters like bit error rate (BER), quality factor (QF), total gain with eye opening factor. It was saw that EDFA provides better results, in the maximal transmission distance 64% better than Raman amplifier, 57.5% for amplification gain and 26.7% for maximum quality factor. As a future study a hybrid amplifier can produce better quality of amplification.
OFDM (Optical Orthogonal Frequency Division Multiplexing) in the optical
domain is an emerging technology for fulfilling increased bit rate demand of real time
sophisticated applications. In this work an optical OFDM system is designed using different
M-ary QAM (Quadrature amplitude Modulation) techniques by varying M to 16, 65, 256.
Performance evaluation has been carried in terms of SNR (Signal to noise ratio) and BER
(bit error rate).In present research OPTSIM and MATLAB has been used as Simulation
tools.
DESIGN AND ANALYSIS OF PHASE-LOCKED LOOP AND PERFORMANCE PARAMETERSIJMEJournal1
In this paper, we are present design and analysis of PLL, which is simulated in CMOS 0.18μm technology.The digital phase locked loop achieves locking within about 100 reference clock cycles. The pure digital
phase locked loop is attractive because it is less sensitive to noise and operating conditions than its analog
counterpart.In this PLL circuit successfully achieved 1.55GHz frequency. Jitter is 1.09ns achieved is very
less. Also achieve low phase noise -98.5827 at 1MHz Frequency
Real Time Implementation of Adaptive Beam former for Phased Array Radar over ...CSCJournals
Mechanical positioners, rotating antennas and large size of early generation radars limited the capability of the radar system to track laterally accelerating targets. Electronic Scanning Array (ESA) such as used in Phased Array Radar (PAR) overcomed these limitations by providing beam agility, good response time, variable scan rates and efficient use of energy. Early PAR systems used analog phase shifting schemes that caused variations and component failures resulting in overall degradation of radar performance. With the advent of new technology and high performance embedded systems, digital beamforming has become powerful enough to perform massive operations required for real time digital beamforming. MATLAB simulation of adaptive beamformer is presented in this paper. Real time implementation of adaptive beamformer over DSP kit (TMS320C6713) was also carried out and results were compared with MATLAB simulations. GUI was also made in MATLAB for viewing results of real time implementation via real time data exchange. Developed system can be used in digital beamforming PAR provided array signals is routed to DSP kit through FPGA interfaced to high speed ADC’s.
PERFORMANCE ASSESSMENT OF MAXIMUM LIKELIHOOD IN THE DETECTION OF CARRIER INTE...IJCNCJournal
Mobile handset carriers are presented as a source of interference to GPS operation in smartphones. The
carriers are presented in terms of their analytical form; block level generation as well as their statistical
distribution model. In addition, we present the analytical form of the received GPS signal corrupted by
carrier interference The Analysis is applied on the chip level in the acquisition engine before stripping the
code or carrier. This expansion will restore the operation of GPS receiver in the presence of carrier
interference. We present an estimate of the amount of improvement that Maximum Likelihood estimation
gives in mitigating carrier interference in smartphones. The amount of improvement is compared to that of
calculations based on measured data processing. The power spectral density of the interference is treated
thoroughly to derive expressions for half of the noise power spectral density.
Design and optimization of a new compact 2.4 GHz-bandpass filter using DGS te...TELKOMNIKA JOURNAL
The objective of this work is the study, the design and the optimization of an innovative structure of a network of coupled copper metal lines deposited on the upper surface of a R04003 type substrate of height 0.813 with a ground deformed by slots (DGS). This structure is designed in an optimal configuration for use in the design of narrowband bandpass filter for wireless communication systems (WLAN), the aim of use the defected ground structure is to remove the unwanted harmonics in the rejection band, the simulation results obtained from this structure using CST software show a very high selectivity of the designed filter, a very low level of losses (less than-0.45 dB) with a size overall size of 43.5x34.3 mm.
Design and optimization of microstrip filtering antenna with modified shaped ...TELKOMNIKA JOURNAL
This paper presents a new compact microstrip filtering antenna with modified shaped slots to improve the impedance bandwidth. The proposed microstrip filtering antenna consists of three parts; the monopole radiating patch antenna, the SIR filter, and the feeding microstrip line. The design structure is achieved on one sided glass epoxy FR-4 substrate with dielectric constant ε_r = 4.4 and thickness of h = 1.6 mm. The design procedures of the proposed filtering antenna starts from the second order Chebyshev low pass filter prototype. The simulation results throughout this article are done by a computer simulation technology (CST) software. The simulated results have been achieved show good performance of S11-parameter and broad side antenna gain on +z-direction. This design has two transmission zeros at 5.4 GHz and 7.7 GHz, and bandwidth (B.W) of about 1.66 GHz so; it is suitable for high speed data communication. This design has good skirt selectivity.
In this paper, UWB technology operating in broad
frequency range of 3.1-10.6 GHz has shown great achievement
for high- speed wireless communications. to satisfy the UWB
system requirements, a band pass filter with a broad pass
band width, low insertion loss, and high stop-band suppression.
UWB band-pass filter (BPF) with wireless local area network
(WLAN) notch at 5.8 GHz and 3-dB fractional bandwidth of
108% using a microstrip structure is presented. Initially a
two transmission pole UWB band pass filter in the frequency
range 3.1-10.6 GHz is achieved by design a parallel-coupled
microstrip line with defective ground plane structure using
GML 1000 substrate with specification: dielectric constant 3.2
and thickness 0.762 mm at centre frequency 6.85 GHz. In this
structure a ë/4 open circuited stub is introduced to achieve the
notch at 5.8 GHz to avoid the interference with WLAN
frequency with lies the desired UWB band. The design
structure was simulated on electromagnetic circuit simulation
software and fabricated by microwave integrated circuit
technique. The measured VNA results show the close
agreement with simulated results.
Comparison of Three Different Cancellation Schemes for Orthogonal Frequency D...ijtsrd
Orthogonal Frequency Division Multiplexing OFDM is an exceptional case of Frequency Division Multiplexing. The dilemma of OFDM is its sensitivity to frequency offset between the transmitted and received carrier frequencies. This frequency offset establishes Inter Carrier Interference ICI Cancellation in the OFDM symbol. ICI reduction methods have been had by OFDM. This research considers three ICI self cancellation SC , maximum likelihood ML estimation, and extended Kalman filter EKF method. These three methods are compared in terms of bit error rate performance, bandwidth efficiency, and computational complexity. For high values of the frequency offset and for higher order modulation schemes, the SC method does not as well as the ML and EKF methods. Simulation results using MATLAB software. Ma Khin Saw | Aye Aye Khine ""Comparison of Three Different Cancellation Schemes for Orthogonal Frequency Division Multiplexing (OFDM) System"" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-3 | Issue-4 , June 2019, URL: https://www.ijtsrd.com/papers/ijtsrd25182.pdf
Paper URL: https://www.ijtsrd.com/engineering/electronics-and-communication-engineering/25182/comparison-of-three-different-cancellation-schemes-for-orthogonal-frequency-division-multiplexing-ofdm-system/ma-khin-saw
Ber performance of ofdm with discrete wavelet transform for time dispersive c...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
BER Analysis of OFDM Systems with Varying Frequency Offset Factor over AWGN a...rahulmonikasharma
The progressively escalating demand for tremendously high rate data transmission over wireless mediums needsresourcefulconcord of electromagnetic resources considering restrictions like power incorporation, spectrum proficiency, robustness in disparity to multipath propagation and implementation complication. Orthogonal frequency division multiplexing (OFDM) is a favorable approach for upcoming generation wireless communication systems. However its susceptibility to the frequency offset triggered by frequency difference between local oscillator of transmitter and receiver or due to Doppler shift results to Inter Carrier Interference. This delinquent of ICI results inworsening performance of the wireless systems as bit error rate increaseswith increase in value of frequency offset. In this paper simulation results aredemonstratedfor analyzing the effect of varying frequency offset factor on system’s error rate performance.
Effects of filtering on ber performance of an ofdm systemeSAT Journals
Abstract In upcoming generations, wireless communication system requires a higher standard in order to provide high quality of services to customers. Orthogonal Frequency Division Multiplexing (OFDM) is an efficient modulation technique of forthcoming wireless systems which can be implemented easily. In this paper, an effort has been made to analyze how well an OFDM system can perform when a signal is transmitted over an Additive White Gaussian Noise (AWGN) channel using 16 QAM modulation techniques. The performance of OFDM system with pulse shaping filters are also evaluated and results reveal that the pulse shaped OFDM improve the overall performance of the system in terms of BER. We use Different pulse shaping filters such asRaised cosine, FIR Nyquist and SQRT Raised Cosine for analyzingthe Bit Error Rate (BER) performance. Index Terms: AWGN, ICI, OFDM, Bit Error Rate.
Transmitting audio via fiber optics under nonlinear effects and optimized tun...IJECEIAES
The ability of fiber optic to overcome the signal transmission problems is making it a dominant transmission medium. Despite of this major positive attribute of optic fibers, there is still a downside for using the fiber optic communication; that is the nonlinearity problem. For the first time, a design of an audio signal is suggested and executed in MATLAB with integration with OptiSystem TM Software .The audio signal then transmitted in different shapes of modulation signals (NRZ, RZ, & RC) for different distances (100 km & 75 km) via a fiber optic media to be received in a receiving part of the simulated system. Three tests are used to do so. The first is the Quality-facto (Q-Factor) against the received power, second test is eye diagram performance and finally is the measuring of the amplitude of output (received) signal for each modulation signal shape using the Oscilloscope Visualizer. The NZR modulation signal was found to be the best one of the three used signals’ types in all three tests. The Q-factor for NRZ pulse shape (=12) was higher than that for RZ (=10) and RC (=8) for a 100 km distance at the same received power level.
Minimize MIMO OFDM interference and noise ratio using polynomial-time algorit...IJECEIAES
In the distributed transmit antenna MIMO OFDM system, each transmitting antenna has different frequency offset between each transmitting antenna and receiver due to the use of independent crystal oscillator. This paper proposes Polynomial-time algorithm for correcting the frequency offset in a received signal by maximizing the conditional average signal. The algorithm focus on reducing to interference and noise ratio of each subcarrier on the receiving antenna by frequency offset. The simulation result shows the performance of the proposed algorithm is slightly improved compared with the existing frequency offset correction algorithm, and the complexity is reduced by 50% or more.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Comparison of various noise mitigation technique used with clipping for reduc...eSAT Journals
Abstract
A simple technique used to reduce the PAPR of OFDM signals is to clip the signal to a maximum allowed value, at the cost of BER
degradation and out-of-band radiation. Clipping does not add extra information to the signal and high peaks occur with low
probability so the signal is seldom distorted. Out-of-band radiation can be reduced by filtering at the transmitter, the filter used in this
project consists on a FFT-IFFT pair which is easier to implement than traditional FIR filters and allows the implementation of the
clip & filter set several times in order to reduce the peak re growth that filtering introduces. The BER degradation can be mitigated by
reconstructing the signal at the receiver. We analyzed the performance of the decision-aided reconstruction (DAR) and improved DAR
(IDAR) techniques that iteratively try to guess the original symbols and proposed an improvement for one of those techniques.
Index Terms: Complementary cumulative distribution function (CCDF),high power amplifier (HPA), Orthogonal
Frequency Division Multiplexing (OFDM), Peak-to-Average Power Ratio (PAPR), inter-symbol interference (ISI)
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Amazon products reviews classification based on machine learning, deep learni...TELKOMNIKA JOURNAL
In recent times, the trend of online shopping through e-commerce stores and websites has grown to a huge extent. Whenever a product is purchased on an e-commerce platform, people leave their reviews about the product. These reviews are very helpful for the store owners and the product’s manufacturers for the betterment of their work process as well as product quality. An automated system is proposed in this work that operates on two datasets D1 and D2 obtained from Amazon. After certain preprocessing steps, N-gram and word embedding-based features are extracted using term frequency-inverse document frequency (TF-IDF), bag of words (BoW) and global vectors (GloVe), and Word2vec, respectively. Four machine learning (ML) models support vector machines (SVM), logistic regression (RF), logistic regression (LR), multinomial Naïve Bayes (MNB), two deep learning (DL) models convolutional neural network (CNN), long-short term memory (LSTM), and standalone bidirectional encoder representations (BERT) are used to classify reviews as either positive or negative. The results obtained by the standard ML, DL models and BERT are evaluated using certain performance evaluation measures. BERT turns out to be the best-performing model in the case of D1 with an accuracy of 90% on features derived by word embedding models while the CNN provides the best accuracy of 97% upon word embedding features in the case of D2. The proposed model shows better overall performance on D2 as compared to D1.
Design, simulation, and analysis of microstrip patch antenna for wireless app...TELKOMNIKA JOURNAL
In this study, a microstrip patch antenna that works at 3.6 GHz was built and tested to see how well it works. In this work, Rogers RT/Duroid 5880 has been used as the substrate material, with a dielectric permittivity of 2.2 and a thickness of 0.3451 mm; it serves as the base for the examined antenna. The computer simulation technology (CST) studio suite is utilized to show the recommended antenna design. The goal of this study was to get a more extensive transmission capacity, a lower voltage standing wave ratio (VSWR), and a lower return loss, but the main goal was to get a higher gain, directivity, and efficiency. After simulation, the return loss, gain, directivity, bandwidth, and efficiency of the supplied antenna are found to be -17.626 dB, 9.671 dBi, 9.924 dBi, 0.2 GHz, and 97.45%, respectively. Besides, the recreation uncovered that the transfer speed side-lobe level at phi was much better than those of the earlier works, at -28.8 dB, respectively. Thus, it makes a solid contender for remote innovation and more robust communication.
Design and simulation an optimal enhanced PI controller for congestion avoida...TELKOMNIKA JOURNAL
In this paper, snake optimization algorithm (SOA) is used to find the optimal gains of an enhanced controller for controlling congestion problem in computer networks. M-file and Simulink platform is adopted to evaluate the response of the active queue management (AQM) system, a comparison with two classical controllers is done, all tuned gains of controllers are obtained using SOA method and the fitness function chose to monitor the system performance is the integral time absolute error (ITAE). Transient analysis and robust analysis is used to show the proposed controller performance, two robustness tests are applied to the AQM system, one is done by varying the size of queue value in different period and the other test is done by changing the number of transmission control protocol (TCP) sessions with a value of ± 20% from its original value. The simulation results reflect a stable and robust behavior and best performance is appeared clearly to achieve the desired queue size without any noise or any transmission problems.
Improving the detection of intrusion in vehicular ad-hoc networks with modifi...TELKOMNIKA JOURNAL
Vehicular ad-hoc networks (VANETs) are wireless-equipped vehicles that form networks along the road. The security of this network has been a major challenge. The identity-based cryptosystem (IBC) previously used to secure the networks suffers from membership authentication security features. This paper focuses on improving the detection of intruders in VANETs with a modified identity-based cryptosystem (MIBC). The MIBC is developed using a non-singular elliptic curve with Lagrange interpolation. The public key of vehicles and roadside units on the network are derived from number plates and location identification numbers, respectively. Pseudo-identities are used to mask the real identity of users to preserve their privacy. The membership authentication mechanism ensures that only valid and authenticated members of the network are allowed to join the network. The performance of the MIBC is evaluated using intrusion detection ratio (IDR) and computation time (CT) and then validated with the existing IBC. The result obtained shows that the MIBC recorded an IDR of 99.3% against 94.3% obtained for the existing identity-based cryptosystem (EIBC) for 140 unregistered vehicles attempting to intrude on the network. The MIBC shows lower CT values of 1.17 ms against 1.70 ms for EIBC. The MIBC can be used to improve the security of VANETs.
Conceptual model of internet banking adoption with perceived risk and trust f...TELKOMNIKA JOURNAL
Understanding the primary factors of internet banking (IB) acceptance is critical for both banks and users; nevertheless, our knowledge of the role of users’ perceived risk and trust in IB adoption is limited. As a result, we develop a conceptual model by incorporating perceived risk and trust into the technology acceptance model (TAM) theory toward the IB. The proper research emphasized that the most essential component in explaining IB adoption behavior is behavioral intention to use IB adoption. TAM is helpful for figuring out how elements that affect IB adoption are connected to one another. According to previous literature on IB and the use of such technology in Iraq, one has to choose a theoretical foundation that may justify the acceptance of IB from the customer’s perspective. The conceptual model was therefore constructed using the TAM as a foundation. Furthermore, perceived risk and trust were added to the TAM dimensions as external factors. The key objective of this work was to extend the TAM to construct a conceptual model for IB adoption and to get sufficient theoretical support from the existing literature for the essential elements and their relationships in order to unearth new insights about factors responsible for IB adoption.
Efficient combined fuzzy logic and LMS algorithm for smart antennaTELKOMNIKA JOURNAL
The smart antennas are broadly used in wireless communication. The least mean square (LMS) algorithm is a procedure that is concerned in controlling the smart antenna pattern to accommodate specified requirements such as steering the beam toward the desired signal, in addition to placing the deep nulls in the direction of unwanted signals. The conventional LMS (C-LMS) has some drawbacks like slow convergence speed besides high steady state fluctuation error. To overcome these shortcomings, the present paper adopts an adaptive fuzzy control step size least mean square (FC-LMS) algorithm to adjust its step size. Computer simulation outcomes illustrate that the given model has fast convergence rate as well as low mean square error steady state.
Design and implementation of a LoRa-based system for warning of forest fireTELKOMNIKA JOURNAL
This paper presents the design and implementation of a forest fire monitoring and warning system based on long range (LoRa) technology, a novel ultra-low power consumption and long-range wireless communication technology for remote sensing applications. The proposed system includes a wireless sensor network that records environmental parameters such as temperature, humidity, wind speed, and carbon dioxide (CO2) concentration in the air, as well as taking infrared photos.The data collected at each sensor node will be transmitted to the gateway via LoRa wireless transmission. Data will be collected, processed, and uploaded to a cloud database at the gateway. An Android smartphone application that allows anyone to easily view the recorded data has been developed. When a fire is detected, the system will sound a siren and send a warning message to the responsible personnel, instructing them to take appropriate action. Experiments in Tram Chim Park, Vietnam, have been conducted to verify and evaluate the operation of the system.
Wavelet-based sensing technique in cognitive radio networkTELKOMNIKA JOURNAL
Cognitive radio is a smart radio that can change its transmitter parameter based on interaction with the environment in which it operates. The demand for frequency spectrum is growing due to a big data issue as many Internet of Things (IoT) devices are in the network. Based on previous research, most frequency spectrum was used, but some spectrums were not used, called spectrum hole. Energy detection is one of the spectrum sensing methods that has been frequently used since it is easy to use and does not require license users to have any prior signal understanding. But this technique is incapable of detecting at low signal-to-noise ratio (SNR) levels. Therefore, the wavelet-based sensing is proposed to overcome this issue and detect spectrum holes. The main objective of this work is to evaluate the performance of wavelet-based sensing and compare it with the energy detection technique. The findings show that the percentage of detection in wavelet-based sensing is 83% higher than energy detection performance. This result indicates that the wavelet-based sensing has higher precision in detection and the interference towards primary user can be decreased.
A novel compact dual-band bandstop filter with enhanced rejection bandsTELKOMNIKA JOURNAL
In this paper, we present the design of a new wide dual-band bandstop filter (DBBSF) using nonuniform transmission lines. The method used to design this filter is to replace conventional uniform transmission lines with nonuniform lines governed by a truncated Fourier series. Based on how impedances are profiled in the proposed DBBSF structure, the fractional bandwidths of the two 10 dB-down rejection bands are widened to 39.72% and 52.63%, respectively, and the physical size has been reduced compared to that of the filter with the uniform transmission lines. The results of the electromagnetic (EM) simulation support the obtained analytical response and show an improved frequency behavior.
Deep learning approach to DDoS attack with imbalanced data at the application...TELKOMNIKA JOURNAL
A distributed denial of service (DDoS) attack is where one or more computers attack or target a server computer, by flooding internet traffic to the server. As a result, the server cannot be accessed by legitimate users. A result of this attack causes enormous losses for a company because it can reduce the level of user trust, and reduce the company’s reputation to lose customers due to downtime. One of the services at the application layer that can be accessed by users is a web-based lightweight directory access protocol (LDAP) service that can provide safe and easy services to access directory applications. We used a deep learning approach to detect DDoS attacks on the CICDDoS 2019 dataset on a complex computer network at the application layer to get fast and accurate results for dealing with unbalanced data. Based on the results obtained, it is observed that DDoS attack detection using a deep learning approach on imbalanced data performs better when implemented using synthetic minority oversampling technique (SMOTE) method for binary classes. On the other hand, the proposed deep learning approach performs better for detecting DDoS attacks in multiclass when implemented using the adaptive synthetic (ADASYN) method.
The appearance of uncertainties and disturbances often effects the characteristics of either linear or nonlinear systems. Plus, the stabilization process may be deteriorated thus incurring a catastrophic effect to the system performance. As such, this manuscript addresses the concept of matching condition for the systems that are suffering from miss-match uncertainties and exogeneous disturbances. The perturbation towards the system at hand is assumed to be known and unbounded. To reach this outcome, uncertainties and their classifications are reviewed thoroughly. The structural matching condition is proposed and tabulated in the proposition 1. Two types of mathematical expressions are presented to distinguish the system with matched uncertainty and the system with miss-matched uncertainty. Lastly, two-dimensional numerical expressions are provided to practice the proposed proposition. The outcome shows that matching condition has the ability to change the system to a design-friendly model for asymptotic stabilization.
Implementation of FinFET technology based low power 4×4 Wallace tree multipli...TELKOMNIKA JOURNAL
Many systems, including digital signal processors, finite impulse response (FIR) filters, application-specific integrated circuits, and microprocessors, use multipliers. The demand for low power multipliers is gradually rising day by day in the current technological trend. In this study, we describe a 4×4 Wallace multiplier based on a carry select adder (CSA) that uses less power and has a better power delay product than existing multipliers. HSPICE tool at 16 nm technology is used to simulate the results. In comparison to the traditional CSA-based multiplier, which has a power consumption of 1.7 µW and power delay product (PDP) of 57.3 fJ, the results demonstrate that the Wallace multiplier design employing CSA with first zero finding logic (FZF) logic has the lowest power consumption of 1.4 µW and PDP of 27.5 fJ.
Evaluation of the weighted-overlap add model with massive MIMO in a 5G systemTELKOMNIKA JOURNAL
The flaw in 5G orthogonal frequency division multiplexing (OFDM) becomes apparent in high-speed situations. Because the doppler effect causes frequency shifts, the orthogonality of OFDM subcarriers is broken, lowering both their bit error rate (BER) and throughput output. As part of this research, we use a novel design that combines massive multiple input multiple output (MIMO) and weighted overlap and add (WOLA) to improve the performance of 5G systems. To determine which design is superior, throughput and BER are calculated for both the proposed design and OFDM. The results of the improved system show a massive improvement in performance ver the conventional system and significant improvements with massive MIMO, including the best throughput and BER. When compared to conventional systems, the improved system has a throughput that is around 22% higher and the best performance in terms of BER, but it still has around 25% less error than OFDM.
Reflector antenna design in different frequencies using frequency selective s...TELKOMNIKA JOURNAL
In this study, it is aimed to obtain two different asymmetric radiation patterns obtained from antennas in the shape of the cross-section of a parabolic reflector (fan blade type antennas) and antennas with cosecant-square radiation characteristics at two different frequencies from a single antenna. For this purpose, firstly, a fan blade type antenna design will be made, and then the reflective surface of this antenna will be completed to the shape of the reflective surface of the antenna with the cosecant-square radiation characteristic with the frequency selective surface designed to provide the characteristics suitable for the purpose. The frequency selective surface designed and it provides the perfect transmission as possible at 4 GHz operating frequency, while it will act as a band-quenching filter for electromagnetic waves at 5 GHz operating frequency and will be a reflective surface. Thanks to this frequency selective surface to be used as a reflective surface in the antenna, a fan blade type radiation characteristic at 4 GHz operating frequency will be obtained, while a cosecant-square radiation characteristic at 5 GHz operating frequency will be obtained.
Reagentless iron detection in water based on unclad fiber optical sensorTELKOMNIKA JOURNAL
A simple and low-cost fiber based optical sensor for iron detection is demonstrated in this paper. The sensor head consist of an unclad optical fiber with the unclad length of 1 cm and it has a straight structure. Results obtained shows a linear relationship between the output light intensity and iron concentration, illustrating the functionality of this iron optical sensor. Based on the experimental results, the sensitivity and linearity are achieved at 0.0328/ppm and 0.9824 respectively at the wavelength of 690 nm. With the same wavelength, other performance parameters are also studied. Resolution and limit of detection (LOD) are found to be 0.3049 ppm and 0.0755 ppm correspondingly. This iron sensor is advantageous in that it does not require any reagent for detection, enabling it to be simpler and cost-effective in the implementation of the iron sensing.
Impact of CuS counter electrode calcination temperature on quantum dot sensit...TELKOMNIKA JOURNAL
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
In place of the commercial Pt electrode used in quantum sensitized solar cells, the low-cost CuS cathode is created using electrophoresis. High resolution scanning electron microscopy and X-ray diffraction were used to analyze the structure and morphology of structural cubic samples with diameters ranging from 40 nm to 200 nm. The conversion efficiency of solar cells is significantly impacted by the calcination temperatures of cathodes at 100 °C, 120 °C, 150 °C, and 180 °C under vacuum. The fluorine doped tin oxide (FTO)/CuS cathode electrode reached a maximum efficiency of 3.89% when it was calcined at 120 °C. Compared to other temperature combinations, CuS nanoparticles crystallize at 120 °C, which lowers resistance while increasing electron lifetime.
A progressive learning for structural tolerance online sequential extreme lea...TELKOMNIKA JOURNAL
This article discusses the progressive learning for structural tolerance online sequential extreme learning machine (PSTOS-ELM). PSTOS-ELM can save robust accuracy while updating the new data and the new class data on the online training situation. The robustness accuracy arises from using the householder block exact QR decomposition recursive least squares (HBQRD-RLS) of the PSTOS-ELM. This method is suitable for applications that have data streaming and often have new class data. Our experiment compares the PSTOS-ELM accuracy and accuracy robustness while data is updating with the batch-extreme learning machine (ELM) and structural tolerance online sequential extreme learning machine (STOS-ELM) that both must retrain the data in a new class data case. The experimental results show that PSTOS-ELM has accuracy and robustness comparable to ELM and STOS-ELM while also can update new class data immediately.
Electroencephalography-based brain-computer interface using neural networksTELKOMNIKA JOURNAL
This study aimed to develop a brain-computer interface that can control an electric wheelchair using electroencephalography (EEG) signals. First, we used the Mind Wave Mobile 2 device to capture raw EEG signals from the surface of the scalp. The signals were transformed into the frequency domain using fast Fourier transform (FFT) and filtered to monitor changes in attention and relaxation. Next, we performed time and frequency domain analyses to identify features for five eye gestures: opened, closed, blink per second, double blink, and lookup. The base state was the opened-eyes gesture, and we compared the features of the remaining four action gestures to the base state to identify potential gestures. We then built a multilayer neural network to classify these features into five signals that control the wheelchair’s movement. Finally, we designed an experimental wheelchair system to test the effectiveness of the proposed approach. The results demonstrate that the EEG classification was highly accurate and computationally efficient. Moreover, the average performance of the brain-controlled wheelchair system was over 75% across different individuals, which suggests the feasibility of this approach.
Adaptive segmentation algorithm based on level set model in medical imagingTELKOMNIKA JOURNAL
For image segmentation, level set models are frequently employed. It offer best solution to overcome the main limitations of deformable parametric models. However, the challenge when applying those models in medical images stills deal with removing blurs in image edges which directly affects the edge indicator function, leads to not adaptively segmenting images and causes a wrong analysis of pathologies wich prevents to conclude a correct diagnosis. To overcome such issues, an effective process is suggested by simultaneously modelling and solving systems’ two-dimensional partial differential equations (PDE). The first PDE equation allows restoration using Euler’s equation similar to an anisotropic smoothing based on a regularized Perona and Malik filter that eliminates noise while preserving edge information in accordance with detected contours in the second equation that segments the image based on the first equation solutions. This approach allows developing a new algorithm which overcome the studied model drawbacks. Results of the proposed method give clear segments that can be applied to any application. Experiments on many medical images in particular blurry images with high information losses, demonstrate that the developed approach produces superior segmentation results in terms of quantity and quality compared to other models already presented in previeous works.
Automatic channel selection using shuffled frog leaping algorithm for EEG bas...TELKOMNIKA JOURNAL
Drug addiction is a complex neurobiological disorder that necessitates comprehensive treatment of both the body and mind. It is categorized as a brain disorder due to its impact on the brain. Various methods such as electroencephalography (EEG), functional magnetic resonance imaging (FMRI), and magnetoencephalography (MEG) can capture brain activities and structures. EEG signals provide valuable insights into neurological disorders, including drug addiction. Accurate classification of drug addiction from EEG signals relies on appropriate features and channel selection. Choosing the right EEG channels is essential to reduce computational costs and mitigate the risk of overfitting associated with using all available channels. To address the challenge of optimal channel selection in addiction detection from EEG signals, this work employs the shuffled frog leaping algorithm (SFLA). SFLA facilitates the selection of appropriate channels, leading to improved accuracy. Wavelet features extracted from the selected input channel signals are then analyzed using various machine learning classifiers to detect addiction. Experimental results indicate that after selecting features from the appropriate channels, classification accuracy significantly increased across all classifiers. Particularly, the multi-layer perceptron (MLP) classifier combined with SFLA demonstrated a remarkable accuracy improvement of 15.78% while reducing time complexity.
Student information management system project report ii.pdfKamal Acharya
Our project explains about the student management. This project mainly explains the various actions related to student details. This project shows some ease in adding, editing and deleting the student details. It also provides a less time consuming process for viewing, adding, editing and deleting the marks of the students.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Final project report on grocery store management system..pdfKamal Acharya
In today’s fast-changing business environment, it’s extremely important to be able to respond to client needs in the most effective and timely manner. If your customers wish to see your business online and have instant access to your products or services.
Online Grocery Store is an e-commerce website, which retails various grocery products. This project allows viewing various products available enables registered users to purchase desired products instantly using Paytm, UPI payment processor (Instant Pay) and also can place order by using Cash on Delivery (Pay Later) option. This project provides an easy access to Administrators and Managers to view orders placed using Pay Later and Instant Pay options.
In order to develop an e-commerce website, a number of Technologies must be studied and understood. These include multi-tiered architecture, server and client-side scripting techniques, implementation technologies, programming language (such as PHP, HTML, CSS, JavaScript) and MySQL relational databases. This is a project with the objective to develop a basic website where a consumer is provided with a shopping cart website and also to know about the technologies used to develop such a website.
This document will discuss each of the underlying technologies to create and implement an e- commerce website.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
Pulse shaping methods for inter carrier interference reduction in OFDM system
1. TELKOMNIKA Telecommunication, Computing, Electronics and Control
Vol. 18, No. 5, October 2020, pp. 2276~2283
ISSN: 1693-6930, accredited First Grade by Kemenristekdikti, Decree No: 21/E/KPT/2018
DOI: 10.12928/TELKOMNIKA.v18i5.13480 2276
Journal homepage: http://journal.uad.ac.id/index.php/TELKOMNIKA
Pulse shaping methods for inter carrier interference reduction in
OFDM system
N. M. A. E. D. Wirastuti1
, Ni Putu Lintang Anggitiadewi2
, Nyoman Pramaita3
1,3
Department of Electrical Engineering, Faculty of Engineering, Udayana University, Indonesia
2
Bali Towerindo Sentra Plc., Indonesia
Article Info ABSTRACT
Article history:
Received Aug 8, 2019
Revised Apr 17, 2020
Accepted May 11, 2020
The weakness of the orthogonal freuency division multiplexing (OFDM)
system is susceptible to the existence of carrier frequency offset (CFO) which
causes the emergence of inter carrier interference (ICI) which causes
a degradation of performance OFDM systems. This study aims to apply
the suggested rectangular (REC) pulse and improved sinc-power (ISP) pulse
shaping methods on OFDM system and determines ICI reduction with
the effects of CFO over flat fading Rayleigh channels. The performance of
each pulse shaping method is evaluated and compared based on parameter ICI
power vs. normalized frequency offset, signal to interference ratio (SIR) vs.
normalized frequency offset and bit error rate (BER) vs. energy bit per noise
(Eb/No). The simulation result in terms of BER vs. Eb/No indicated that REC
and ISP pulse shaping has better performance dealing with ICI reduction
compared to OFDM system no applied pulse shaping. In addition, the ISP is
able to mitigate ICI better than REC.
Keywords:
ICI
ISP pulse
OFDM
Pulse shaping
Rectangular pulse
This is an open access article under the CC BY-SA license.
Corresponding Author:
N. M. A. E. D. Wirastuti,
Department of Electrical Engineering,
Faculty of Engineering, Udayana University,
Kampus UNUD Road, Bukit Jimbaran, Kuta Selatan, Badung-Bali-80361, Indonesia.
Email: dewi.wirastuti@unud.ac.id
1. INTRODUCTION
OFDM is a multicarrier transmission technique which between subcarriers are arranged to be mutually
overlapping and arranged in such a way so that between subcarriers will have orthogonal properties [1, 2].
By using this overlapping technique, OFDM systems offer high bandwidth efficiency that save up to 50% [3].
It also has high data rate transmission capability and robust to multipath fading and delay. It able to convert
a frequency selective fading channel into several nearly flat fading channels as the entire available spectrum is
divided into a number of narrow-band subchannels. Due to its advantages, OFDM has been identified as one
of the prime technologies for use in the next generation of heterogeneous wireless networks.
However, one of the main disadvantages of OFDM is its susceptible to carrier frequency offset (CFO)
which can arise due to the Doppler effect and frequency mismatches of the transmitter and receiver oscillators.
The interference affected by frequency offset will cause orthogonality losses between OFDM scheme’s
subcarriers and results in the emergence of inter carrier interference (ICI) which can reduce the performance
of the OFDM system [4]. Therefore, an action is needed to mitigate ICI in OFDM systems.
Several methods have been introduced to mitigate ICI such as pulse shaping [5-10], frequency domain
equalization [11], ICI self-cancellation schemes [12], windowing [13] at the receiver and Maximum likelihood
estimation technique (MLE) [14]. In this paper, pulse shaping methods have been considered due to its
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Pulse shaping methods for inter carrier interference reduction in OFDM system (N. M. A. E. D. Wirastuti)
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simplicity and efficiency [15]. The pulse shaping method is the most effective method that can be used to
overcome the main causes of ICI in OFDM systems because with the implementation of pulse shaping,
the subcarrier will be filtered when it is still mutually orthogonal so that when it arrives at the receiver,
the effect of interference from another subcarrier will be reduced [5].
The use of Nyquist-I pulses to reduce the ICI power in OFDM-based systems has been
proposed [6, 7, 16, 17] such as the raised cosine (RC) pulse, “better than” raised cosine (BTRC) pulse, sinc
power (SP) pulse, improved sinc power (ISP) pulse and rectangular (REC) pulse. Currently, the ISP is probably
that has the best performance in dealing with ICI due to frequency offset in OFDM systems. In this paper,
the proposed implementation of REC and ISP pulse was proposed with variations of normalized frequency
offset. A simulation model for assessing the performance of REC and ISP pulse was introduced using OFDM
system in a flat fading Rayleigh channel.
2. RESEARCH METHOD
A simulation method was used to evaluate the performance of REC pulse and ISP pulse in reducing
ICI due to frequency offset effects on OFDM system over flat fading Rayleigh channel. Simulations have been
performed in order to compare the performance of the OFDM systems, with and without pulse shaping.
The performance of REC pulse and ISP pulse were also observed using the variation of normalized frequency
offsets. The parametes used to evaluate including ICI power vs. normalized frequency offset, signal to
interference ratio (SIR) vs. normalized frequency offset and bit error rate (BER) vs. energy bit per noise
(Eb/No).
2.1. Modelling ICI
For system modeling that experiences ICI effect, it is stated in (1) as follows [3].
𝑠𝑠′ 𝑚𝑚 = �𝑠𝑠𝑚𝑚 𝑃𝑃(−∆𝑓𝑓) + ∑ 𝑠𝑠𝑘𝑘 𝑃𝑃𝑁𝑁−1
𝑘𝑘=0
𝑘𝑘≠𝑚𝑚
�
𝑚𝑚−𝑘𝑘
𝑇𝑇
− ∆𝑓𝑓�� 𝑒𝑒𝑗𝑗𝑗𝑗
+ 𝑛𝑛 𝑚𝑚 (1)
The ICI effect on the received symbol is expressed as Δf variable called CFO. The next CFO will be normalized
to the subcarrier spacing (∆𝑓𝑓𝑐𝑐) which is called the normalized frequency offset (ΔfT). That ΔfT
or ε shows how much the subcarrier shifted is detected by the receiver oscillator where |ΔfT|≤1.
In the simulation model, the formula is excuted after the output of parallel to serial. The magnitude of
the normalized frequency offset used in this paper was calculated using (2) as follows [18]:
𝜀𝜀 =
𝑓𝑓𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜𝑜
∆𝑓𝑓𝑐𝑐
(2)
In this paper, to determine normalized frequency offset variations, we use a set of frequency offset
including 2 kHz, 4 kHz and 5 kHz that represent for large and small subcarrier shifted. In accordance with
the fixed WiMAX standard, the subcarrier spacing (∆𝑓𝑓𝑐𝑐) used was 9765 Hz and using (2), the normalized
frequency offset can be found as follows;
Frequency offset = 2 kHz = 2000 Hz
𝜀𝜀 =
∆𝑓𝑓
∆𝑓𝑓𝑐𝑐
=
2000
9765
= 0,2.
Frequency offset = 4 kHz, 𝜀𝜀 = 0.4.
Frequency offset = 5 kHz, 𝜀𝜀 = 0.5.
ICI power states the magnitude power of ICI that generated from OFDM system after the implementation of
pulse shaping to reduce ICI in OFDM systems where the amount of ICI power generated can be calculated
using (3) as follows [18].
𝜎𝜎𝐼𝐼𝐼𝐼𝐼𝐼 𝑚𝑚
2
= ∑ ∑ 𝑠𝑠𝑚𝑚 𝑠𝑠𝑛𝑛
∗𝑁𝑁−1
𝑛𝑛=0
𝑘𝑘≠0
𝑃𝑃 �
𝑘𝑘−𝑚𝑚
𝑇𝑇
− ∆𝑓𝑓� 𝑃𝑃 �
𝑛𝑛−𝑚𝑚
𝑇𝑇
− ∆𝑓𝑓�𝑁𝑁−1
𝑛𝑛=0
𝑘𝑘≠0
(3)
Signal to interference ratio (SIR) states the ratio of magnitude of received signal strength to interference
between subcarriers. The magnitude of SIR is expressed using (4) as follows [19];
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SIR =
|𝑃𝑃(∆𝑓𝑓)|2
∑ |𝑃𝑃�
𝑘𝑘−𝑚𝑚
𝑇𝑇0
+ ∆𝑓𝑓�|2𝑁𝑁−1
𝑛𝑛=0
𝑘𝑘≠0
(4)
2.2. Pulse shaping function
This function acts to form a pulse of existing symbols. Each symbol that is transmitted will be
multiplied by pulse shaping function. The use of pulse shaping method is to eliminate the side lobe power
which can potentially generate ICI power. So that the use of pulse shaping can reduce ICI power due to
the frequency offset [20]. The pulse function in the frequency domain was used in this paper as follows [3].
− REC pulse
𝑃𝑃𝑟𝑟𝑟𝑟𝑟𝑟(𝑓𝑓) = 𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠(𝑓𝑓𝑓𝑓) , (5)
then the frequency offset is substituted to (5)
𝑃𝑃𝑟𝑟𝑟𝑟𝑟𝑟(∆𝑓𝑓) = 𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠(∆𝑓𝑓𝑓𝑓) (6)
− ISP pulse
𝑃𝑃𝐼𝐼𝐼𝐼𝐼𝐼(𝑓𝑓) = 𝑒𝑒−𝑎𝑎(𝑓𝑓𝑓𝑓)2
𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 𝑛𝑛
(𝑓𝑓𝑓𝑓) (7)
then the frequency offset is substituted to (7)
𝑃𝑃𝐼𝐼𝐼𝐼𝐼𝐼(∆𝑓𝑓) = 𝑒𝑒−𝑎𝑎(∆𝑓𝑓𝑓𝑓)2
𝑠𝑠𝑠𝑠𝑠𝑠𝑠𝑠 𝑛𝑛
(∆𝑓𝑓𝑓𝑓) (8)
For ISP pulse, there are variables, a and n, according to [21]. The performance improvement of OFDM
system can survive if the parameter a = 1 and n = 2. The spectrum of ISP and REC pulse can be seen
in Figure 1 [22]. Figure 1 illustrates ISP pulse (in brown line) has the same side lobe power as zero compared
to the side lobe of the REC pulse (in blue line). Due to the value of side lobe is zero, then when the subcarrier
shifted to the orthogonal position of the side lobe, the interference will not affect the other subcarriers.
On the other hand, for REC pulse, the power of the side lobe cannot be maximally reduced due to the subcarrier
shifted that will causes interference of other subcarriers [18]. The purpose of using pulse shaping method is
to eliminate side lobes that can potentially generate ICI power. The use of ISP pulse can reduce ICI power
from the side lobe better than the REC pulse [3].
Figure 1. Spectrum of ISP and REC pulse
2.3. Simulation model
We consider ISP dan REC pulse applied to the OFDM system in a flat fading Rayleigh channel as
shown in Figure 2 [20, 23, 24]. The pulse shaping function was applied at the transmitter. Flat fading Rayleigh
channel was used where each channel response that is Rayleigh distributed [25] with adding addictive white
Gaussian noise (AWGN). The parameters used in this simulation were based on fixed wireless worldwide
interoperability for microwave access (WiMAX) standard as shown in Table 1.
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Figure 2. ISP dan REC pulse applied to the OFDM system over flat fading Rayleigh channels
Table 1. Parameter simulation
Parameter Values
Input Bit Random 100.000 bits
Type of modulation QPSK
FFT size 64
Number of subcarriers 64
Number of data subcarriers 52
Cyclic prefix Lengths 16
Type of channel AWGN + flat fading Rayleigh
Normalized frequency offset (ε) 0.2, 0.4 and 0.5
Frequency offset 2 kHz, 4 kHz, 5 kHz
Subcarrier spacing 9.765 kHz
Eb/No 0:2:20
Pulse shaping ISP & REC pulse
3. RESULTS AND ANALYSIS
Simulations have been performed in order to evaluate and compare the performance of OFDM
systems, with and without pulse shaping, in reducing ICI with effects of CFO. The simulation uses
the parameters discussed in section 2.3. The simulation model is presented in Figure 2. We also present
performance comparison of REC and ISP pulse using normalized frequency offset variations in order to assess
the effects of normalized frequency offset on OFDM system performance. The performance of each pulse
shaping method is evaluated and compared based on parameter ICI power vs. normalized frequency offset and
signal to interference ratio (SIR) vs. normalized frequency offset. The BER vs. Eb/No performance for OFDM
system, with and without pulse shaping, is examined and compared in the case of an AWGN and flat Rayleigh
fading channel.
3.1. BER performance with a normalized frequency offset
Figure 3 presents BER performance of OFDM system, with and without pulse shaping, in case of
fading channel. Both pulse shaping, REC and ISP pulse, evaluated and compared, in order to investigate
the effect of CFO. The normalized frequency offset used was about 0.2. At an Eb/No of 10 dB, the BER for
OFDM systems without pulse shaping is about 0.0180 while BER for OFDM systems with REC and ISP were
0.0090 and 0.0056, respectively. The use of pulse shaping has given better performance than OFDM with no
pulse shaping. Futhermore, OFDM system performance with applied ISP pulse has shown better performance
than REC pulse. This was indicated by the BER performance of ISP pulse lower than REC pulse. It has
happened due to ISP pulse affected to the side lobe of each subcarrier to be zero power (flat). When ICI arises,
there will be no shifted in subcarriers side lobe. Therefore, the subcarriers do not lose its orthogonality and will
not cause interference between subcarriers [26, 27]. Thus, it can be concluded that the use of pulse shaping can
provide an increase in OFDM system performance because the interference effects of subcarriers can be
minimized using reducing ICI power in side lobe. ISP pulse was able to reduce ICI better than REC pulse.
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Figure 3. BER vs. Eb/No of OFDM System, without and with REC and ISP pulse
3.2. BER performance with normalized frequency offset variations
Figure 4 depicts BER performance of OFDM system, without and with pulse shaping, using variations
of normalized frequency offset. The normalized frequency offset was referred to (2). So, the normalized
frequency offset (𝜀𝜀) used in the simulation were 0.2, 0.4 and 0.5. From Figure 4, it can be seen that BER
performance comparison of REC and ISP pulse applied to OFDM system, with 𝜀𝜀 = 0.5, was given the worst
BER performance. Normalized frequency offset is expressed as a subcarrier shifted that caused by frequency
offset. So that, if the subcarrier frequency shifted or normalized frequency offset is greater, the effect of
interference from other subcarriers accordingly will be greater and the ICI power produced will increase.
Thus, it can be concluded that the greater the normalized frequency offset, the OFDM system performance will
be worse. It is due to the higher the offset frequency effected to the OFDM system so that the ICI power
generated will also be greater. From the simulation results, it can also be seen that BER performance of OFDM
system with ISP pulse was able provided better performance than REC pulse [25-27].
Figure 4. Performance of OFDM system with normalized frequency offset variations
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3.3. ICI power and SIR analysis
Refered to the (3) and (4), ICI power and signal to interference ratio (SIR) were generated after
the implementation of ISP and REC pulse. The performance of REC and ISP pulse based on parameter ICI
power vs. normalized frequency offset and SIR vs. normalized frequency offset, can be illustrated in
Figures 5 and 6, respectively. Figure 5 shows that at normalized offset frequency, 𝜀𝜀 = 0.2, REC pulse applied
to OFDM system created ICI power about -10.9723 dB, which is higher than applied ISP pulse to OFDM
system, about -42.6542 dB. Important trend can be observed from this simulation result that in highest
normalized frequency offset resulting the smallest ICI power. So, ICI power inversely proportional to
normalized frequency offset.
From Figure 6, it can be seen that SIR performance for REC pulse applied to OFDM system was
smaller than SIR performance for ISP pulse. At 𝜀𝜀 = 0.2, SIR performance of REC pulse applied to OFDM
system was about 13.0045 dB while ISP pulse applied to OFDM system was about 38.0214 dB. The important
trend can be observed that SIR performance inversely proportional to normalized frequency offset where
the higher normalized frequency offset resulting lower SIR performance.
The higher SIR and smaller ICI power will cause the better performance of OFDM system. The use
of ISP pulse can improve OFDM system performance better than REC pulse due to ISP pulse minimizing ICI
power better than REC pulse. By minimizing the ICI power, it results the lower risk of orthogonality losses
between OFDM scheme’s subcarriers. This causes SIR in OFDM system increasing and OFDM system
performance tends to be better.
Figure 5. ICI power comparison of REC and ISP pulse
Figure 6. SIR performance comparison of REC and ISP pulse
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4. CONCLUSION
In this paper, the implementation of pulse shaping techniques, REC and ISP pulse, have been
introduced. REC and ISP pulse applied to OFDM system has been evaluated and compared to suppress
the effect of ICI with the presence of CFO over fading channel. The ISP pulse performed better than REC
pulse. It is due to that ISP pulse is able to minimize ICI power better than REC pulse. It also was able to produce
higher SIR compared to REC pulse. So generally, by using pulse shaping, the performance of OFDM system
seems to be better because of the implementation of pulse shaping reduces the side lobe power of a subcarrier
which potentially cause ICI. Therefore, with the use of pulse shaping, a side lobe subcarrier will not interference
to other subcarriers. The performance of OFDM system will degrade that effected by the presence of CFO,
the higher frequency offset will increase ICI power.
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BIOGRAPHIES OF AUTHORS
N. M. A. E. D. Wirastuti received the B.Eng. degree in electrical engineering from Udayana
University, Bali, Indonesia, in 2000, the M.Sc. degree in mobile communication systems
from University of Surrey, Guildford, United Kingdom, in 2002 and the Ph.D. degree in
Telecommunication Systems from University of Bradford, West Yorkshire, United
Kingdom, in 2007. From 2007 to 2009, she was a Post Doctoral Fellowship with the Mobile
and Satellite Communication Research Centre (MSCRC), University of Bradford, United
Kingdom worked to the VeSeL (Village e-Science for Life) project, Engineering and
Physical Sciences Research Council (EPSRC) grant. Dr. Wirastuti was a recipient of the
Best Paper Student in 2006 from University of Bradford for paper presentation at INTI
College, Malaysia. Her research interest includes the development of physical layer model
for the next wireless and mobile communication systems. She has been a lecturer in
Department of Electrical Engineering, Faculty of Engineering at Udayana University, Bali,
Indonesia, since 2001.
Ni Putu Lintang Anggitiadewi received the B.Eng. degree in electrical engineering from
Udayana University, Bali, Indonesia, in 2019. Currently, she is working as PMO Network
Planning Staff at Bali Towerindo Sentra Plc. Bali, Indonesia.
Nyoman Pramaita received the first degree in Electrical engineering from Brawijaya
University, Malang, Indonesia, in 1995, the Master degree in Electrical engineering from
The Institute of Sepuluh Nopember, Surabaya, Indonesia, in 2003, and the Ph.D degree in
Electronic and Electrical engineering from Liverpool John Moore University, Liverpool,
UK. He has been a lecturer in Electrical engineering at Udayana University since 1997.
He is currently the head of Telecommunication Engineering Laboratory in Electrical
engineering at Udayana University.