The document discusses channel estimation techniques for MIMO-OFDM systems using QAM and QPSK modulation. It investigates least squares (LS), minimum mean square error (MMSE), and discrete Fourier transform (DFT) based channel estimation. LS and MMSE techniques are used to estimate the channel at pilot subcarriers. Time-domain interpolation is then applied to estimate channels at data subcarriers. Simulation results show that applying DFT to the estimated channel powers improves the performance of channel estimators, especially for QPSK modulation.
This document discusses channel estimation techniques in OFDM systems. It compares LS and MMSE estimation methods. It also describes simulating an OFDM transmission in Matlab to analyze how the bit error ratio is affected by changing the signal-to-noise ratio and multipath effects. The key steps of the simulation are outlined, including OFDM transmission, channel estimation using LS and MMSE, and calculating the bit error ratio to compare performance of the estimation techniques.
Performances des turbo codes parallèles pour un canal satellite non linéaireRachidz
1) The document analyzes the performance of parallel concatenated codes (turbo codes) with iterative decoding for error correction on nonlinear satellite channels.
2) It simulates a digital satellite transmission system using parallel turbo codes with QPSK modulation.
3) The simulation evaluates how varying parameters like constraint length, interleaver size, and number of iterations affects the bit error rate performance of turbo codes compared to Viterbi decoding.
This document evaluates the performance of different sonar signals using fusion techniques. It discusses Linear Frequency Modulated (LFM) pulses, Gaussian Nonlinear Frequency Modulated (NLFM) pulses, and Rayleigh NLFM pulses. It generates a new fusion signal combining LFM, Gaussian NLFM, and Rayleigh NLFM signals. The ambiguity functions and range resolution plots of the individual and fusion signals are compared. Parameters like discrimination, merit factor, peak to sidelobe level ratio, and integrated sidelobe level ratio are calculated. The fusion signal is found to provide better range resolution and parameter values compared to the individual signals. Therefore, fusing different sonar signals can improve system performance and target detection capabilities.
Radionet Communications provides capabilities in land mobile radio systems including tuning, testing, and repairing subscriber units; programming units to work on federal and interoperability systems; and managing interoperability gateway deployments. They have experience programming units for conventional and trunked systems and deploying a regional interoperability system for the Navy Region Northeast. Radionet can also provide consulting services, perform radio frequency coverage simulations using open-source software, conduct system drive testing, and develop communications procedures and protocols.
This document discusses digital communication systems and provides an overview of several key topics:
- It introduces line coding techniques and their properties.
- It describes the basic digital communication block diagram and advantages of digital transmission.
- It discusses intersymbol interference, equalization techniques like zero-forcing equalization, and eye patterns.
- It provides information on topics like noise immunity, regenerative repeaters, and pulse shaping to eliminate intersymbol interference.
This document discusses digital baseband communication systems and line coding techniques. It provides an overview of the key steps in analog-to-digital conversion: sampling, quantization, mapping, and encoding/pulse shaping. It then describes several common line coding schemes used to transmit the digital bit stream over physical channels, including unipolar, polar, and bipolar encoding. The advantages and disadvantages of each scheme are discussed in terms of properties like DC balance, clock recovery, energy, and bandwidth.
COMMUNICATION ENGINEERING ASSIGNMENT(INSTITUTE ELECTIVE-1) SEM-4 SVMITVishal Soni
The document provides instructions for several experiments involving amplitude modulation transmitter and receiver circuits, including circuits for DSB-AM, SSB-AM, and DSB-AM with AGC. Diagrams of the circuits are included, along with procedures to observe waveforms, adjust frequencies and gains, and measure modulation index. Students are to record their observations and conclusions from completing the experiments.
A BICMOS chipset for a DVB-H front-end receiverRFIC-IUMA
This document describes a BiCMOS chipset for a DVB-H front-end receiver implemented in a 0.35 μm BiCMOS process. Key components include a low noise amplifier (LNA) with a minimum gain of 13 dB and noise figure of 3 dB, a mixer with conversion gain of 10.7 dB and maximum noise figure of 22.5 dB, and a voltage controlled oscillator (VCO) that oscillates from 1085 MHz to 1766 MHz with a phase noise of -112 dBc/Hz. Measurement results show the LNA/mixer combination achieves a conversion gain of 28.5 dB and total noise figure of 8.4 dB. In addition, a synthesizer for the DVB
This document discusses channel estimation techniques in OFDM systems. It compares LS and MMSE estimation methods. It also describes simulating an OFDM transmission in Matlab to analyze how the bit error ratio is affected by changing the signal-to-noise ratio and multipath effects. The key steps of the simulation are outlined, including OFDM transmission, channel estimation using LS and MMSE, and calculating the bit error ratio to compare performance of the estimation techniques.
Performances des turbo codes parallèles pour un canal satellite non linéaireRachidz
1) The document analyzes the performance of parallel concatenated codes (turbo codes) with iterative decoding for error correction on nonlinear satellite channels.
2) It simulates a digital satellite transmission system using parallel turbo codes with QPSK modulation.
3) The simulation evaluates how varying parameters like constraint length, interleaver size, and number of iterations affects the bit error rate performance of turbo codes compared to Viterbi decoding.
This document evaluates the performance of different sonar signals using fusion techniques. It discusses Linear Frequency Modulated (LFM) pulses, Gaussian Nonlinear Frequency Modulated (NLFM) pulses, and Rayleigh NLFM pulses. It generates a new fusion signal combining LFM, Gaussian NLFM, and Rayleigh NLFM signals. The ambiguity functions and range resolution plots of the individual and fusion signals are compared. Parameters like discrimination, merit factor, peak to sidelobe level ratio, and integrated sidelobe level ratio are calculated. The fusion signal is found to provide better range resolution and parameter values compared to the individual signals. Therefore, fusing different sonar signals can improve system performance and target detection capabilities.
Radionet Communications provides capabilities in land mobile radio systems including tuning, testing, and repairing subscriber units; programming units to work on federal and interoperability systems; and managing interoperability gateway deployments. They have experience programming units for conventional and trunked systems and deploying a regional interoperability system for the Navy Region Northeast. Radionet can also provide consulting services, perform radio frequency coverage simulations using open-source software, conduct system drive testing, and develop communications procedures and protocols.
This document discusses digital communication systems and provides an overview of several key topics:
- It introduces line coding techniques and their properties.
- It describes the basic digital communication block diagram and advantages of digital transmission.
- It discusses intersymbol interference, equalization techniques like zero-forcing equalization, and eye patterns.
- It provides information on topics like noise immunity, regenerative repeaters, and pulse shaping to eliminate intersymbol interference.
This document discusses digital baseband communication systems and line coding techniques. It provides an overview of the key steps in analog-to-digital conversion: sampling, quantization, mapping, and encoding/pulse shaping. It then describes several common line coding schemes used to transmit the digital bit stream over physical channels, including unipolar, polar, and bipolar encoding. The advantages and disadvantages of each scheme are discussed in terms of properties like DC balance, clock recovery, energy, and bandwidth.
COMMUNICATION ENGINEERING ASSIGNMENT(INSTITUTE ELECTIVE-1) SEM-4 SVMITVishal Soni
The document provides instructions for several experiments involving amplitude modulation transmitter and receiver circuits, including circuits for DSB-AM, SSB-AM, and DSB-AM with AGC. Diagrams of the circuits are included, along with procedures to observe waveforms, adjust frequencies and gains, and measure modulation index. Students are to record their observations and conclusions from completing the experiments.
A BICMOS chipset for a DVB-H front-end receiverRFIC-IUMA
This document describes a BiCMOS chipset for a DVB-H front-end receiver implemented in a 0.35 μm BiCMOS process. Key components include a low noise amplifier (LNA) with a minimum gain of 13 dB and noise figure of 3 dB, a mixer with conversion gain of 10.7 dB and maximum noise figure of 22.5 dB, and a voltage controlled oscillator (VCO) that oscillates from 1085 MHz to 1766 MHz with a phase noise of -112 dBc/Hz. Measurement results show the LNA/mixer combination achieves a conversion gain of 28.5 dB and total noise figure of 8.4 dB. In addition, a synthesizer for the DVB
4g LTE and LTE-A for mobile broadband-notePei-Che Chang
This document discusses the basic principles of OFDM (Orthogonal Frequency Division Multiplexing) transmission. It covers several key topics:
1) OFDM uses multiple subcarriers to transmit data in parallel. The subcarriers are spaced closely together with minimal spacing between them.
2) OFDM modulation and demodulation can be implemented efficiently using IDFT/DFT (IFFT/FFT) processing.
3) Cyclic prefixes are added to combat inter-symbol interference from multipath channels. This preserves subcarrier orthogonality.
4) With a cyclic prefix, the channel appears flat on each subcarrier, allowing one-tap frequency domain equalization. Channel estimation is done using reference symbols.
The document contains contents and procedures for experiments in a communication lab manual, including building and testing second-order active filters (low-pass, high-pass, band-pass, and band-elimination), determining their frequency responses, and calculating their roll-offs. Tables are provided to record input and output voltages and gains at different frequencies to characterize the filters. Instructions ensure equipment is tested before experiments and guide building the filter circuits according to given specifications.
This document discusses different types of analog-to-analog modulation techniques used in analog transmission including amplitude modulation, frequency modulation, and phase modulation. Amplitude modulation varies the amplitude of the carrier signal based on the modulating signal. Frequency modulation varies the frequency of the carrier signal based on the modulating signal. Phase modulation only changes the phase of the carrier signal which manifests as a frequency change. The document provides equations to calculate the bandwidth requirements for each modulation technique based on the bandwidth of the modulating signal.
The document discusses various modes of data transmission including simplex, half-duplex, and full-duplex transmission. It also covers parallel versus serial transmission and describes how parallel transmission uses multiple wires while serial transmission uses just two wires. The document then discusses modulation techniques for data transmission over telephone lines using modems as well as synchronization techniques for digital modulation including asynchronous and synchronous methods.
Noise and Bandwidth Consideration in Designing Op-Amp Based Transimpedance Am...journalBEEI
In a visible light communication (VLC) system, there are many modules involved. One of the important modules is Transimpedance Amplifier (TIA) that resides in the analog front-end receiver (Rx-AFE). TIA is responsible for performing signal conversion from current signal, which is provided from the photodiode (PD) to voltage signal. It is the reason why the TIA should be operating in low noise condition and wide bandwidth of frequency. These will enable a flexible coverage of the VLC system in performing its signal processing. Hence, in this research, we provide considerations of the noise and frequency bandwidth analysis in designing TIA to cope with the required design specification of a VLC system.
This document provides an overview of the H.264 video compression standard. It describes the standard's basic concepts and important features/algorithms in detail. Compared to previous standards, H.264 achieves coding improvements of at least 2 dB in PSNR and 40% bit rate savings. The standard supports various block sizes, motion compensation, transform coding, quantization, entropy coding, and flexible slice ordering to improve compression performance.
This document summarizes a research paper that investigates the effect of different orthogonal frequency division multiplexing (OFDM) transmission modes on the performance of carrier frequency offset (CFO) estimation using a cyclic prefix-based synchronization technique. Five transmission modes are tested (0.25K, 0.5K, 1K, 2K, 4K) by developing an OFDM system simulation in MATLAB. The results show that synchronization performance, as measured by mean squared error of CFO estimation, improves with increasing transmission mode/IFFT size but requires more estimation time. Larger transmission modes provide better frequency synchronization.
UNIT III BASEBAND TRANSMISSION
Properties of Line codes- Power Spectral Density of Unipolar / Polar RZ & NRZ – Bipolar NRZ - Manchester- ISI – Nyquist criterion for distortionless transmission – Pulse shaping – Correlative coding - Mary schemes – Eye pattern – Equalization
This document discusses various methods of digital-to-analog conversion for analog transmission of digital data. It describes techniques such as amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK), and quadrature amplitude modulation (QAM). For each method, it discusses how the digital data modulates an analog carrier signal, provides examples of implementation, and examines bandwidth requirements. It also introduces constellation diagrams to depict signal amplitudes and phases for modulation schemes involving multiple carriers.
This document discusses regenerative repeaters and communication link budgets. It begins by explaining how regenerative repeaters detect and regenerate signals to boost the signal strength along the transmission path without amplifying noise. It then provides examples of calculating error probabilities for systems with regenerative vs analog repeaters. Next, it outlines the parameters considered in a communication link budget, such as transmitter power, antenna gains and losses. Finally, it works through an example link budget calculation for a geosynchronous satellite system.
This document discusses various methods of digital-to-analog conversion for analog transmission of digital data. It describes techniques such as amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK), and quadrature amplitude modulation (QAM). For each method, it discusses how the digital data modulates an analog carrier signal, provides equations for calculating bandwidth, and includes examples demonstrating how to apply the techniques. Diagrams and constellation plots are also used to illustrate the different modulation schemes.
Linear Ic Applications Jntu Model Paper{Www.Studentyogi.Com}guest3f9c6b
This document contains questions from past exam papers for the subject "Linear IC Applications". It includes 8 questions related to topics like differential amplifiers, op-amps, filters, oscillators, timers, DACs, ADCs and multiplexers. Students are required to answer any 5 questions out of the 8 questions provided. The questions test the students' understanding of circuit analysis and design of various applications using linear integrated circuits.
1 RB sensitivity at middle RBs poor than other RBsPei-Che Chang
1. Measuring LTE sensitivity with a single resource block (RB) located in the middle of the channel can degrade sensitivity. This is because control channels like the primary synchronization signal (PSS), secondary synchronization signal (SSS) and physical broadcast channel (PBCH) are also located in the middle, making decoding more difficult.
2. With a single middle RB, the coding rate needs to be twice as high on subframe 0 compared to other subframes to achieve the same block error rate. This requires at least 3dB higher signal-to-noise ratio (SNR).
3. Testing sensitivity with few RBs near the channel center can also degrade sensitivity slightly due to interference from the in-band
This document discusses analog transmission techniques. It covers digital-to-analog conversion methods like ASK, FSK, PSK and QAM. It then discusses analog-to-analog modulation techniques like amplitude modulation, frequency modulation and phase modulation. It provides examples of calculating the bandwidth requirements for different modulation schemes and how analog signals are allocated specific frequency bands for transmission.
This document describes the design of two stepped impedance microstrip low pass filters with defected ground structures (DGS). The first is a 7th order filter with 3 interdigital DGS slots that achieves less than 0.97 dB insertion loss and less than 10 ps group delay variation. The second is a 9th order filter that uses different DGS shapes including rectangular, square dumbbell, and interdigital, achieving 0.5 dB insertion loss and 27 ps group delay variation. Both filters have a cutoff frequency of 16 GHz and were analyzed using simulation software before being fabricated on a substrate for testing, with simulated and measured results showing good agreement.
This document discusses different types of analog-to-analog modulation techniques used in analog transmission including amplitude modulation, frequency modulation, and phase modulation. Amplitude modulation varies the amplitude of the carrier signal based on the modulating signal. Frequency modulation varies the frequency of the carrier signal based on the modulating signal. Phase modulation only changes the phase of the carrier signal which manifests as a frequency change. The document provides equations to calculate the bandwidth requirements for each modulation technique based on the bandwidth of the modulating signal.
This document discusses various analog and digital modulation techniques used to transmit digital and analog signals. It provides examples of calculating bit rates, baud rates, and bandwidth requirements for different modulation schemes including ASK, FSK, PSK, QAM, AM, and FM. Key modulation techniques covered are the modulation of a digital signal using digital-to-analog conversion and modulation of an analog signal using amplitude, frequency, or phase modulation.
The document outlines various digital modulation techniques including ASK, BPSK, and FSK. It describes how each technique generates and detects modulated signals. ASK encodes data in signal amplitude levels. BPSK uses two phase shift keying to encode bits. FSK encodes data by shifting the carrier frequency between two values. Optimum detection requires coherent demodulation that correlates the received signal with a reference carrier.
Short survey for Channel estimation using OFDM systemsMohamed Seif
This document discusses channel estimation techniques for OFDM systems. It begins by introducing OFDM and the need for channel state information at the receiver. It then describes two common pilot arrangements - block and comb type. For block pilots, it examines least squares and minimum mean square error channel estimation. It finds MMSE performs better but with higher complexity. For comb pilots, it presents least squares and LMS estimation as well as interpolation techniques between pilot tones. The document also evaluates channel estimation for MIMO-OFDM and the effects of user mobility.
1. The document is a dissertation submitted by Zhongshan Wu to Louisiana State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical and Computer Engineering.
2. The dissertation focuses on channel estimation for MIMO-OFDM systems and wireless location techniques for OFDM-based systems like WiMax.
3. In the first part, the dissertation formulates the channel estimation problem for MIMO-OFDM systems and proposes a pilot-tone based estimation algorithm using a least squares approach. In the second part, it addresses the wireless location problem in WiMax networks and develops techniques for location estimation based on time difference of arrival, angle of arrival, or a combination of the two
Implementation of channel estimation algorithms in ofdm for 64 subcarriersIAEME Publication
The document discusses channel estimation algorithms in OFDM systems with 64 subcarriers. It compares the performance of least squares (LS), linear minimum mean square error (LMMSE), and modified MMSE channel estimation algorithms for different modulation schemes including PSK and QAM. Simulation results show that the modified MMMSE algorithm, which considers a reduced channel correlation matrix, achieves a lower symbol error rate than LS and LMMSE, especially at high SNRs, with reduced computational complexity compared to LMMSE.
4g LTE and LTE-A for mobile broadband-notePei-Che Chang
This document discusses the basic principles of OFDM (Orthogonal Frequency Division Multiplexing) transmission. It covers several key topics:
1) OFDM uses multiple subcarriers to transmit data in parallel. The subcarriers are spaced closely together with minimal spacing between them.
2) OFDM modulation and demodulation can be implemented efficiently using IDFT/DFT (IFFT/FFT) processing.
3) Cyclic prefixes are added to combat inter-symbol interference from multipath channels. This preserves subcarrier orthogonality.
4) With a cyclic prefix, the channel appears flat on each subcarrier, allowing one-tap frequency domain equalization. Channel estimation is done using reference symbols.
The document contains contents and procedures for experiments in a communication lab manual, including building and testing second-order active filters (low-pass, high-pass, band-pass, and band-elimination), determining their frequency responses, and calculating their roll-offs. Tables are provided to record input and output voltages and gains at different frequencies to characterize the filters. Instructions ensure equipment is tested before experiments and guide building the filter circuits according to given specifications.
This document discusses different types of analog-to-analog modulation techniques used in analog transmission including amplitude modulation, frequency modulation, and phase modulation. Amplitude modulation varies the amplitude of the carrier signal based on the modulating signal. Frequency modulation varies the frequency of the carrier signal based on the modulating signal. Phase modulation only changes the phase of the carrier signal which manifests as a frequency change. The document provides equations to calculate the bandwidth requirements for each modulation technique based on the bandwidth of the modulating signal.
The document discusses various modes of data transmission including simplex, half-duplex, and full-duplex transmission. It also covers parallel versus serial transmission and describes how parallel transmission uses multiple wires while serial transmission uses just two wires. The document then discusses modulation techniques for data transmission over telephone lines using modems as well as synchronization techniques for digital modulation including asynchronous and synchronous methods.
Noise and Bandwidth Consideration in Designing Op-Amp Based Transimpedance Am...journalBEEI
In a visible light communication (VLC) system, there are many modules involved. One of the important modules is Transimpedance Amplifier (TIA) that resides in the analog front-end receiver (Rx-AFE). TIA is responsible for performing signal conversion from current signal, which is provided from the photodiode (PD) to voltage signal. It is the reason why the TIA should be operating in low noise condition and wide bandwidth of frequency. These will enable a flexible coverage of the VLC system in performing its signal processing. Hence, in this research, we provide considerations of the noise and frequency bandwidth analysis in designing TIA to cope with the required design specification of a VLC system.
This document provides an overview of the H.264 video compression standard. It describes the standard's basic concepts and important features/algorithms in detail. Compared to previous standards, H.264 achieves coding improvements of at least 2 dB in PSNR and 40% bit rate savings. The standard supports various block sizes, motion compensation, transform coding, quantization, entropy coding, and flexible slice ordering to improve compression performance.
This document summarizes a research paper that investigates the effect of different orthogonal frequency division multiplexing (OFDM) transmission modes on the performance of carrier frequency offset (CFO) estimation using a cyclic prefix-based synchronization technique. Five transmission modes are tested (0.25K, 0.5K, 1K, 2K, 4K) by developing an OFDM system simulation in MATLAB. The results show that synchronization performance, as measured by mean squared error of CFO estimation, improves with increasing transmission mode/IFFT size but requires more estimation time. Larger transmission modes provide better frequency synchronization.
UNIT III BASEBAND TRANSMISSION
Properties of Line codes- Power Spectral Density of Unipolar / Polar RZ & NRZ – Bipolar NRZ - Manchester- ISI – Nyquist criterion for distortionless transmission – Pulse shaping – Correlative coding - Mary schemes – Eye pattern – Equalization
This document discusses various methods of digital-to-analog conversion for analog transmission of digital data. It describes techniques such as amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK), and quadrature amplitude modulation (QAM). For each method, it discusses how the digital data modulates an analog carrier signal, provides examples of implementation, and examines bandwidth requirements. It also introduces constellation diagrams to depict signal amplitudes and phases for modulation schemes involving multiple carriers.
This document discusses regenerative repeaters and communication link budgets. It begins by explaining how regenerative repeaters detect and regenerate signals to boost the signal strength along the transmission path without amplifying noise. It then provides examples of calculating error probabilities for systems with regenerative vs analog repeaters. Next, it outlines the parameters considered in a communication link budget, such as transmitter power, antenna gains and losses. Finally, it works through an example link budget calculation for a geosynchronous satellite system.
This document discusses various methods of digital-to-analog conversion for analog transmission of digital data. It describes techniques such as amplitude shift keying (ASK), frequency shift keying (FSK), phase shift keying (PSK), and quadrature amplitude modulation (QAM). For each method, it discusses how the digital data modulates an analog carrier signal, provides equations for calculating bandwidth, and includes examples demonstrating how to apply the techniques. Diagrams and constellation plots are also used to illustrate the different modulation schemes.
Linear Ic Applications Jntu Model Paper{Www.Studentyogi.Com}guest3f9c6b
This document contains questions from past exam papers for the subject "Linear IC Applications". It includes 8 questions related to topics like differential amplifiers, op-amps, filters, oscillators, timers, DACs, ADCs and multiplexers. Students are required to answer any 5 questions out of the 8 questions provided. The questions test the students' understanding of circuit analysis and design of various applications using linear integrated circuits.
1 RB sensitivity at middle RBs poor than other RBsPei-Che Chang
1. Measuring LTE sensitivity with a single resource block (RB) located in the middle of the channel can degrade sensitivity. This is because control channels like the primary synchronization signal (PSS), secondary synchronization signal (SSS) and physical broadcast channel (PBCH) are also located in the middle, making decoding more difficult.
2. With a single middle RB, the coding rate needs to be twice as high on subframe 0 compared to other subframes to achieve the same block error rate. This requires at least 3dB higher signal-to-noise ratio (SNR).
3. Testing sensitivity with few RBs near the channel center can also degrade sensitivity slightly due to interference from the in-band
This document discusses analog transmission techniques. It covers digital-to-analog conversion methods like ASK, FSK, PSK and QAM. It then discusses analog-to-analog modulation techniques like amplitude modulation, frequency modulation and phase modulation. It provides examples of calculating the bandwidth requirements for different modulation schemes and how analog signals are allocated specific frequency bands for transmission.
This document describes the design of two stepped impedance microstrip low pass filters with defected ground structures (DGS). The first is a 7th order filter with 3 interdigital DGS slots that achieves less than 0.97 dB insertion loss and less than 10 ps group delay variation. The second is a 9th order filter that uses different DGS shapes including rectangular, square dumbbell, and interdigital, achieving 0.5 dB insertion loss and 27 ps group delay variation. Both filters have a cutoff frequency of 16 GHz and were analyzed using simulation software before being fabricated on a substrate for testing, with simulated and measured results showing good agreement.
This document discusses different types of analog-to-analog modulation techniques used in analog transmission including amplitude modulation, frequency modulation, and phase modulation. Amplitude modulation varies the amplitude of the carrier signal based on the modulating signal. Frequency modulation varies the frequency of the carrier signal based on the modulating signal. Phase modulation only changes the phase of the carrier signal which manifests as a frequency change. The document provides equations to calculate the bandwidth requirements for each modulation technique based on the bandwidth of the modulating signal.
This document discusses various analog and digital modulation techniques used to transmit digital and analog signals. It provides examples of calculating bit rates, baud rates, and bandwidth requirements for different modulation schemes including ASK, FSK, PSK, QAM, AM, and FM. Key modulation techniques covered are the modulation of a digital signal using digital-to-analog conversion and modulation of an analog signal using amplitude, frequency, or phase modulation.
The document outlines various digital modulation techniques including ASK, BPSK, and FSK. It describes how each technique generates and detects modulated signals. ASK encodes data in signal amplitude levels. BPSK uses two phase shift keying to encode bits. FSK encodes data by shifting the carrier frequency between two values. Optimum detection requires coherent demodulation that correlates the received signal with a reference carrier.
Short survey for Channel estimation using OFDM systemsMohamed Seif
This document discusses channel estimation techniques for OFDM systems. It begins by introducing OFDM and the need for channel state information at the receiver. It then describes two common pilot arrangements - block and comb type. For block pilots, it examines least squares and minimum mean square error channel estimation. It finds MMSE performs better but with higher complexity. For comb pilots, it presents least squares and LMS estimation as well as interpolation techniques between pilot tones. The document also evaluates channel estimation for MIMO-OFDM and the effects of user mobility.
1. The document is a dissertation submitted by Zhongshan Wu to Louisiana State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Electrical and Computer Engineering.
2. The dissertation focuses on channel estimation for MIMO-OFDM systems and wireless location techniques for OFDM-based systems like WiMax.
3. In the first part, the dissertation formulates the channel estimation problem for MIMO-OFDM systems and proposes a pilot-tone based estimation algorithm using a least squares approach. In the second part, it addresses the wireless location problem in WiMax networks and develops techniques for location estimation based on time difference of arrival, angle of arrival, or a combination of the two
Implementation of channel estimation algorithms in ofdm for 64 subcarriersIAEME Publication
The document discusses channel estimation algorithms in OFDM systems with 64 subcarriers. It compares the performance of least squares (LS), linear minimum mean square error (LMMSE), and modified MMSE channel estimation algorithms for different modulation schemes including PSK and QAM. Simulation results show that the modified MMMSE algorithm, which considers a reduced channel correlation matrix, achieves a lower symbol error rate than LS and LMMSE, especially at high SNRs, with reduced computational complexity compared to LMMSE.
This document lists 21 potential Matlab project topics covering areas such as signal processing, computer vision, biometrics, medical imaging, and power systems. The projects involve developing algorithms and models for tasks like channel estimation, object tracking, image fusion, system identification, and optimization problems in power grid operation and economic dispatch.
International Journal of Modern Engineering Research (IJMER) is Peer reviewed, online Journal. It serves as an international archival forum of scholarly research related to engineering and science education.
International Journal of Engineering and Science Invention (IJESI)inventionjournals
International Journal of Engineering and Science Invention (IJESI) is an international journal intended for professionals and researchers in all fields of computer science and electronics. IJESI publishes research articles and reviews within the whole field Engineering Science and Technology, new teaching methods, assessment, validation and the impact of new technologies and it will continue to provide information on the latest trends and developments in this ever-expanding subject. The publications of papers are selected through double peer reviewed to ensure originality, relevance, and readability. The articles published in our journal can be accessed online.
This document proposes a semiblind channel estimation approach for MIMO-OFDM systems that combines training-based and blind techniques. It derives a linear prediction-based blind constraint and incorporates it into a training-based least squares cost function using a weighting factor. A perturbation analysis justifies the superiority of the semiblind solution and derives a closed-form expression for the mean square error of the blind constraint, facilitating the calculation of the optimal weighting factor. Computer simulations show the proposed semiblind approach achieves very high channel estimation accuracy compared to purely training-based or blind methods.
This document provides contact information for VENSOFT Technologies and describes 25 MATLAB projects for the 2013-2014 academic year related to signal processing topics such as phase noise estimation in MIMO systems, distributed averaging algorithms, channel estimation, computation of the moment generating function for lognormal distributions, compressed sensing of EEG data, and compressed sensing for wireless monitoring of fetal ECG signals. The contact for projects is provided as VENSOFT Technologies, their website, and a phone number.
VLSI Implementation of OFDM Transceiver for 802.11n systemsIJERA Editor
This document describes the VLSI implementation of a 4x4 MIMO-OFDM transceiver for 802.11n systems using a Spartan 6 FPGA. The transceiver uses OFDM modulation with 64-bit FFT and 1/2 rate encoding. It was designed and tested on a Diligent Atlys FPGA board with a wired channel. Performance was analyzed by measuring BER and data rate with varying SNR. Data rates up to 216 Mbps were achieved with 16QAM modulation. The design was implemented and tested using Matlab Simulink, Xilinx tools, and hardware co-simulation between Simulink and the FPGA board.
This document provides an overview of channel estimation strategies used in orthogonal frequency division multiplexing (OFDM) systems. It describes the basic types of channel estimation methods: block-type pilot channel estimation and comb-type pilot channel estimation. For block-type estimation, pilots are inserted into all subcarriers of OFDM symbols periodically. This allows estimation of the channel conditions between pilot symbols. Estimation can be done with least squares (LS), minimum mean-square error (MMSE), or modified MMSE. For comb-type estimation, pilots are inserted into certain subcarriers of each symbol, requiring interpolation to estimate data subcarriers. The document compares the implementation complexity and performance of different estimation methods.
This document presents a project report on a novel channel equalization technique for MIMO-OFDM systems and a study of WPMCM systems. The project was completed by 5 students under the guidance of Ms. R. Deepa to fulfill the requirements for a Bachelor of Technology degree in Electronics and Communication Engineering from Amrita School of Engineering, Coimbatore.
The report includes chapters on MIMO systems, OFDM and WPMCM, MIMO-OFDM and MIMO-WPMCM, channel estimation techniques for OFDM and MIMO-OFDM, and a novel pre-distortion type adaptive channel equalization technique. Simulation results are presented to analyze the performance and effectiveness of the proposed channel
This document describes a script that simulates bit error rate (BER) performance for BPSK modulation over a Rayleigh fading channel with a 2 transmitter and 2 receiver (2x2) multiple-input multiple-output (MIMO) system using zero forcing equalization. The script generates transmitted bits, applies BPSK modulation, sends the signals over a Rayleigh fading channel with additive noise, uses zero forcing equalization at the receiver, and compares the estimated and transmitted bits to calculate the simulated BER over a range of signal-to-noise ratio (SNR) values. The simulated results are then plotted along with theoretical BER curves for 1x1 and 2x2 MIMO systems.
This Matlab code simulates OFDM channel estimation using a PN sequence as a cyclic prefix. It generates transmitted OFDM signals, adds channel effects using different multipath delay profiles, and estimates the channel using three methods: conventional correlation, correlation with two-tap filter estimation, and interpolation of periodically inserted PN sequences. It compares the bit error rates of the three channel estimation methods under varying signal-to-noise ratios.
The document provides an overview of LTE physical layer specifications including OFDMA frame structure, resource block structure, protocol architecture, physical channel structure and procedures, UE measurements like RSRP and RSRQ, and key enabling technologies of LTE such as OFDM, SC-FDMA, and MIMO. It describes the LTE requirements for high peak data rates, low latency, support for high mobility users, and enhanced broadcast services.
This document discusses modeling wireless communication systems using MATLAB. It covers:
- Characterizing the wireless channel from physics of propagation to multi-path fading channels.
- Statistical characterization of channels including Doppler spectrum, delay spread, coherence time and bandwidth.
- Simulating multi-path fading channels in MATLAB and modeling path loss.
- Explaining how multi-path propagation leads to signal distortion and is equivalent to undesired filtering.
The document discusses channel modeling and Kalman filter-based estimation for OFDM wireless communication systems. It provides an introduction to OFDM systems and outlines the channel modeling process, including modeling the channel as a multipath frequency selective fading channel using a tapped delay line. It also discusses implementing channel estimation using a Kalman filter and presenting results on simulating OFDM signal transmission through a Rayleigh fading channel. The goal is to accurately estimate the channel fading parameters using a joint time-frequency domain estimation model.
1) The document presents channel estimation methods for MIMO-OFDM systems using QPSK modulation.
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IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Phydyas 09 fFilter Bank Multicarrier (FBMC): An Integrated Solution to Spectr...Marwan Hammouda
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Comparative evaluation of bit error rate for different ofdm subcarriers in ra...ijmnct
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Join us for a LIVE WEBINAR on this topic! Wednesday, November 14, 2:00pm ET
http://bit.ly/XPgjO7
Wide bandwidth modulation is becoming more common in communications. The emergence of the 802.11ac wireless Ethernet standard has extended the modulation bandwidth to 160 MHz which requires very wide band measurement equipment to measure. This presentation illustrates the details of a measurement method that uses a real time digital down converter and post processing software that measures the performance of this signal.
IRJET- Review of Orthogonal Frequency Division Multiplexing for Wireless ...IRJET Journal
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CS Based Channel Estimation for OFDM Systems under Long Delay Channels Using ...IJERA Editor
Orthogonal frequency division multiplexing (OFDM) is a technique which are used in the next-generation wireless communication. Channel estimation in the OFDM technique is one of the big challenges, ever since high-resolution channel estimation can significantly improve the equalization at the receiver and consequently enhance the communication performances. Channel computation using superimposed pilot sequences is also a fully new area, idea for using superimposed pilot sequences has been proposed by various authors for different applications. In this paper, we are introduced a high accurate, low complexity compressive sensing (CS) based channel estimation namely Auxiliary information based Subspace Pursuit (ASP) in TFT-OFDM systems. ASP based channel estimation in TFT-OFDM system is based on two steps. First is, by exploiting the signal structure of recently proposed TDM-OFDM scheme, the supporting channel information is obtained. Second is, we propose the supporting information based subspace pursuit (SP) algorithm to use a very small amount of frequency domain pilots embedded in the OFDM block used for the exact channel estimation. Moreover, the obtained auxiliary channel information is adopted to reduce the complexity of the conventional SP algorithm. Simulation results demonstrate a important reduction of the number of pilots relative to least-squares channel estimation and supporting high-order modulations like 256 QAM.
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2) It introduces the impulse response model used to model multipath channels. The received signal is a combination of multipath components that arrive at different times with different amplitudes and phases.
3) It discusses parameters used to characterize mobile multipath channels including mean excess delay, RMS delay spread, maximum excess delay, coherence bandwidth, Doppler spread, and coherence time. These parameters describe the time dispersion and time-varying nature of the channel.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
This document discusses various digital modulation techniques. It begins by explaining binary amplitude-shift keying (ASK), where one amplitude encodes a 0 and another encodes a 1. It then discusses on-off keying (OOK) and multiple amplitude shift keying (MASK). Next, it covers frequency-shift keying (FSK), phase-shift keying (PSK), differential PSK, and quadrature PSK. It also discusses more advanced modulations like quadrature amplitude modulation (QAM), continuous phase modulation (CPM), and Gaussian minimum-shift keying. The document provides examples and discusses the pros, cons, and applications of different modulation schemes. It concludes by discussing a student project involving designing and analyzing a digital
1. The document provides definitions and explanations of key concepts in digital communication systems and coding techniques. It contains questions and answers on topics like modulation, sampling theorem, equalization, coding, and error correction.
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3. Error correction techniques like Hamming codes, BCH codes, and RS codes are described in terms of their parameters, capabilities, and decoding methods. The differences between block codes and convolutional codes are also summarized.
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IJCER (www.ijceronline.com) International Journal of computational Engineering research
1. International Journal Of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5
Investigation on Channel Estimation techniques for MIMO- OFDM
System for QAM/QPSK Modulation
Rajbir Kaur1, Charanjit Kaur2
1
Assistant Prof., ECE, University College of Engineering, Punjabi University, Patiala, India,
2
Student, ECE, University College of Engineering, Punjabi University, Patiala, India
Abstract:
Multiple Input Multiple Output (MIMO) systems has provide high transmission data rate without increasing transmitting
power for wireless communication systems. The performance can be further improved by properly estimating the channel at
the receiver side. In this paper, investigation on various channel estimation techniques for MIMO-OFDM has been done and a
new approach based on time-domain interpolation (TDI) has been presented. TDI is obtained by transforming output of
estimator to time domain through Inverse Discrete Fourier Transform (IDFT), zero padding and going back to frequency
domain through Discrete Fourier Transform (DFT). The comparison has been carried out between power of true channel and
estimated power for the given channel using LS, LS-Spline and MMSE for QPSK/QAM modulation at SNR 30dB. It is
investigated that by applying the DFT over the estimated power of channel for QPSK, the performance of the channel
estimators becomes better.
Keywords: Channel estimation, Discrete Fourier transform (DFT), Least square error (LS), Minimum mean square error
(MMSE), MIMO-OFDM, QAM, QPSK.
1. Introduction
MIMO-OFDM is an important part of modern wireless communication standards such as IEEE 802.11n, 4G, 3GPP LTE and
WiMAX [1]. It can eliminate the effect of frequency selective fading and significantly increase both the system’s capacity and
spectral efficiency. The data rate can be increased by spatial multiplexing without consuming more frequency resources and
without increasing the total transmit power.
The performance of the system depends generally on modulation schemes, channel estimation techniques used to estimate
channel. The capacity of communication system increases linearly with the number of antennas, when perfect knowledge
about the channel is available at the receiver. In practice, the channel estimation procedure is done by transmitting pilot
(training) symbols that are known at the receiver. Further, channel estimation depends on the pattern of transmitting pilots.
Block type and comb type patterns have been considered in this paper. LSE, MMSE algorithms have been used to estimate the
channel. Simulations and comparisons are carried out for QPSK and QAM data using LSE, MMSE algorithms with and
without DFT.
In this paper channel impulse response has been estimated and compared using LS, MMSE and DFT based estimation
techniques. The paper is organized as follows. In Section 2, MIMO system is described. Section 3 discusses Channel
Estimation in MIMO-OFDM System. Section 4 describes channel estimation based on DFT. Simulation and results for the
performance of LS, MMSE and DFT based techniques are given in section 5. Section 6 concludes the paper.
2. MIMO System
MIMO communication uses multiple antennas at both the transmitter and receiver to exploit the spatial domain for spatial
multiplexing and/or spatial diversity. Spatial multiplexing [2]-[3] has been generally used to increase the capacity of a MIMO
link by transmitting independent data streams in the same time slot and frequency band simultaneously from each transmit
antenna, and differentiating multiple data streams at the receiver using channel information about each propagation path. In
contrast to spatial multiplexing, the purpose of spatial diversity is to increase the diversity order of a MIMO link to mitigate
fading by coding a signal across space and time so that a receiver could receive the replicas of the signal and combine those
received signals constructively to achieve a diversity gain.
Issn 2250-3005(online) September| 2012 Page 1419
2. International Journal Of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5
Figure 1. (a) Spatial Multiplexing (b) Spatial Diversity
Fig. 1.1 depicts a MIMO-OFDM [4] system consists of NT transmitter antennas, NR receiver antennas and K number of
sub-carriers. Each transmitter (or receiver) antenna uses an ordinary OFDM modulator (or demodulator). a ( r ) ( n) denotes
th
OFDM symbol generated in r transmitted antenna for nth time index, before transmitting the vector is processed by an
Lg
Lg B1
P/S S/P
1
A
S/P IFFT 1 1 FFT
K-point
Bk
Lg
Lg B1
P/S S/P
S/P IFFT FFT
ANT
NT NR K-point
Bk
Figure 2. MIMO-OFDM
Inverse Fast Fourier Transform (IFFT) block with K points and a CP of length Lg is added to its beginning. The lengths of CP
have to fulfill the inequality of Lg ≥ L −1 in which L is the maximum length of channel impulse response (CIR) among all
sub-channels. At the receiver, after discarding the CP, OFDM symbol is received after processing Fast Fourier Transform
(FFT) [5].
3. Channel Estimation in MIMO-OFDM System
An accurate estimate of the impulse response of the channel can be obtained, if the receiver has a prior knowledge of the
information being sent over the channel. The pilots are transmitted on all subcarriers in periodic intervals of OFDM blocks for
a slow fading channel, where the channel is constant over a few OFDM symbols and this type of pilot arrangement is known
as block type pilot arrangement. The pilots are transmitted at all times but with an even spacing on the subcarriers,
representing a comb type pilot placement as shown in Fig. 3 for a fast fading channel, where the channel changes between
adjacent OFDM symbols. With interpolation techniques the estimation of channel at data subcarrier can be obtained using
channel estimation at pilot subcarriers [6].
Issn 2250-3005(online) September| 2012 Page 1420
3. International Journal Of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5
Figure 3. Block Type Pilot Arrangement and Comb Type Pilot Arrangement [6]
In this paper, whereas LS- Spline, piece-wise, second order, time domain interpolation technique has been employed for
estimating channel at data subcarriers.
3.1. Channel estimation at pilot subcarriers
Various algorithms such as Least Square (LS), Minimum MMSE have been employed for estimating channel at pilot
subcarriers.
3.1.1. Least Square (LS) Algorithm
Let A is the diagonal matrix of pilots as A diag A0 , A1 , , AN 1 , N is the number of pilots in one OFDM symbol, h is
ˆ
the impulse response of the pilots of one OFDM symbol, and Z is the AWGN channel noise.
If there is no ISI, the signal received is written as [10]
ˆ
B AFh Z (1)
where B the vector of output signal is after OFDM demodulation as B B0 , B1 , , BN 1 , T
ˆ
H LS A1 B (2)
Because of no consideration of noise and ICI, LS algorithm is simple, but obviously it suffers from a high MSE.
3.1.2. Minimum Mean Square Error
If the channel and AWGN are not correlated, MMSE estimate of H is given by [11]
ˆ 1
H MMSE SHB SBB B (3)
where SHB E HB H
SHH AH
SBB E BB H ASHH AH Z I N
2
are the cross covariance matrix between H and B , and auto-covariance matrix of B respectively. S HH is auto-covariance
matrix of H . Z is the noise-variance. If S HH and Z are known to the receiver, CIR could be calculated by MMSE
2 2
estimator as below
1
AH LS SHH S HH Z AH A
1 1
ˆ
H MMSE SHB SBB B SHH AH ASHH AH Z I N
1 2 ˆ 2 ˆ
H LS (4)
Eb
At lower value of
N 0 the performance of MMSE estimator is much better than LS estimator. MMSE estimator could gain
10-15 dB more of performance than LS.
3.2. Channel estimation at data subcarriers
In order to estimate channel at data sub-carriers by using the channel information at pilot sub-carriers, an efficient
interpolation technique is necessary in comb-type pilot based channel estimation.
3.2.1. Piecewise Constant Interpolation
Channel is estimated by previous pilot in Piecewise constant interpolation. And the channel estimation is given by,
H k H lM m H p l ,
ˆ ˆ ˆ 0 m M, l 0,1, , N p 1 (5)
where M = No. of subcarriers (N)/ No. of pilot (Np)
l = pilot carrier index.
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3.2.2. Cubic Spline Interpolation
The cubic spline interpolation is given by [52],
H k H lM m
ˆ ˆ
c1 H p l 1 c0 H p l Mc1 H l 1 Mc0 H l
ˆ ˆ ˆ
p
ˆ
p
l 0,1, , N p 1 0 m M, (6)
where M = No. of subcarriers (N)/ No. of pilot (Np)
l = pilot carrier index.
H l is the first order derivative of H p l , and
ˆ
p
ˆ
3 M m 2 M m
2 3
c1
M2 M3
3m2 2m3
c0 2 3 (7)
M M
Cubic spline interpolation with higher order interpolation can be used for better interpolation accuracy.
4. Channel Estimation Based On DFT
Application of DFT on LS, MMSE channel estimation can improve the performance of estimators by eliminating the effect of
noise.
Let H k denote the estimate of channel gain at the kth subcarrier, obtained by either LS or MMSE channel estimation
ˆ
method. Taking the IDFT of the channel estimate
N 1
ˆ
H [k ] , ˆ
k 0 ˆ
IDFT H [k ] h[n] z[n] h[n], n 0,1,..., N 1 (8)
where z[n] denotes the noise component in the time domain. Eliminate the impact of noise in time domain, and thus achieve
higher estimation accuracy.
ˆ h[n] z[n], n 0,1, 2,..., L 1
hDFT [n] (9)
0, otherwise
Taking the DFT remaining L elements to transform in frequency domain [12-14]
ˆ ˆ
H DFT [k ] DFT hDFT (n) (10)
Simulations are carried out for channel estimation using LS-Linear, LS-spline, MMSE methods for QPSK and QAM
modulation schemes. The Simulation results show that the performance of DFT based channel estimator is much better over
the LS, MMSE estimator in case of QPSK, but the symbol rate decreases. Fig. 2, 3 and 4 represents the performance of above
mentioned channel estimator with and without DFT.
5. Simulations and Results
In this simulation work, first the random pilot sequence of length 8, where X p {1,1} and data sequence of length 24,
a {0,15} are generated. Sequence ‘a’ is modulated using 16-QAM at SNR = 20dB, 30dB, 40dB. The pilot symbols are
inserted in the modulated data sequence using pilot duration of 4 symbols and forms a new data sequence A. After pilot
insertion data sequence A is converted into time domain sequence using 32-point IFFT and 4 symbol CP is added, the resultant
sequence is denoted as ‘at’. The guard interval or the length of the CP is longer than the maximum delay spread of the channel.
The sequence ‘at’ is then transmitted over a randomly generated 3-tap channel. AWGN is added to the received signal. The CP
is removed from the noise corrupted received signal which is then subject to FFT. Now, since the transmitted pilots and
received pilots are known, the CSI is estimated using LS Linear, LS-Spline Interpolation and MMSE.
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5. International Journal Of Computational Engineering Research (ijceronline.com) Vol. 2 Issue. 5
LS with and without DFT LS with and without DFT
10 10
5 5
Power[dB]
Power[dB]
0 True Channel 0 True Channel
LS without DFT LS without DFT
-5 LS with DFT -5 LS with DFT
0 5 10 15 20 25 30 0 5 10 15 20 25 30
Subcarrier Index Subcarrier Index
LS -SPLINE with and without DFT LS -SPLINE with and without DFT
10 10
5 5
Power[dB]
Power[dB]
0 True Channel 0 True Channel
LS-SPLINE without DFT LS-SPLINE without DFT
-5 LS-SPLINE with DFT -5 LS-SPLINE with DFT
0 5 10 15 20 25 30 0 5 10 15 20 25 30
Subcarrier Index Subcarrier Index
MMSE with and without DFT MMSE with and without DFT
10 10
5 5
Power[dB]
Power[dB]
0 True Channel 0 True Channel
MMSE without DFT MMSE without DFT
-5 MMSE with DFT -5 MMSE with DFT
0 5 10 15 20 25 30 0 5 10 15 20 25 30
Subcarrier Index Subcarrier Index
QPSK QAM
Figure 4. Performance of MIMO-OFDM System using various Channel Estimations with and without DFT for QPSK
and QAM at SNR 30 dB
In the simulations, the power of true channel and power obtained by using this estimation have been considered. The detectors
at the receiver utilize this estimated channel to obtain the information out of the received signal which is then demodulated to
get random bits. It is observed that simulation results become better if the estimated output from various estimators is subject
to DFT. For subcarrier index 10, true channel power comes out to be 7.294dB. The simulations have been also calculated
using LS linear for 10th subcarrier index for QPSK at SNR=30dB and the estimated power is calculated as 6.879dB and result
improved by 0.57 dB with application of DFT technique. For LS-spline without DFT, the estimated power is calculated to be
7.225dB, whereas on applying DFT performance of this estimation technique is improved by 0.003 dB. For MMSE the
estimated power is calculated as 7.205 dB and performance improved by 0.0.021 dB on applying MMSE with DFT. For LS-
spline without DFT for 10th subcarrier index at SNR=30dB for QAM the estimated power is calculated to be 7.207dB.
Whereas on applying DFT over this estimation technique gives 7.204 dB of power. For MMSE the estimated power for 10th
subcarrier index at SNR=20dB for QAM is calculated as 7.173 dB and performance improved by 0.29 dB on applying MMSE
with DFT. At higher SNR=40dB, Estimated power using LS linear, for 10th subcarrier index for QAM is calculated as
6.902dB whereas on applying DFT over this estimation technique, the simulation results improved by 0.65 dB. Simulation
results show that MMSE with DFT performs better than other estimations at the cost of computational complexity. The
number of symbol errors in case of QPSK is 2 whereas in case of QAM value become 22.
6. Conclusion
MIMO-OFDM has the capability of transmitting information at high data rate without increasing the transmitting power. The
performance of the system can be improved by estimating the channel parameters effectively. From the simulations it is
concluded MMSE algorithm estimates the channel much better than LS at the cost of increasing complexity. The results
improve when the output of estimator is subject to DFT. Moreover it is observed the QPSK data symbols results in less
number of errors as compared to QAM at cost of decrease in symbol rate. A trade off has made for the performance of MIMO-
OFDM system among complexity, symbol rate and symbol errors.
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