At this present scenario, the demand of the system capacity is very high in wireless network. MIMO
technology is used from the last decade to provide this requirement for wireless network antenna
technology. MIMO channels are mostly used for advanced antenna array technology. But it is most
important to control the error rate with enhanced system capacity in MIMO for present-day progressive
wireless communication. This paper explores the frame error rate with respect to different path gain of
MIMO channel. This work has been done in different fading scenario and produces a comparative analysis
of MIMO on the basis of those fading models in various conditions. Here, it is to be considered that
modulation technique as QPSK to observe these comparative evaluations for different Doppler frequencies.
From the comparative analysis, minimum amount of frame error rate is viewed for Rician distribution at
LOS path Doppler shift of 0 Hz. At last, this work is concluded with a comparative bit error rate study on
the basis of singular parameters at different SNR levels to produce the system performance for uncoded
QPSK modulation.
Bit Error Rate Performance of MIMO Spatial Multiplexing with MPSK Modulation ...ijsrd.com
Wireless communication is one of the most effective areas of technology development of our time. Wireless communications today covers a very wide array of applications. In this, we study the performance of general MIMO system, the general V-BLAST architecture with MPSK Modulation in Rayleigh fading channels. Based on bit error rate, we show the performance of the 2x2 schemes with MPSK Modulation in noisy environment. We also show the bit error rate performance of 2x2, 3x3, 4x4 systems with BPSK modulation. We see that the bit error rate performance of 2x2 systems with QPSK modulation gives us the best performance among other schemes analysed here.
Performance Analysis of Various Symbol Detection Techniques in Wireless MIMO ...IOSR Journals
Wireless communication is one of the most effective areas of technology development of our time.
Wireless communications today covers a very wide array of applications. In this paper, we study the
performance of general MIMO system, the performance of Zero Forcing (ZF), Linear Least Square Estimator
(LLSE), V-BLAST/ZF, V-BLAST/LLSE of 4x4, 4x6 & 4x8 with 4-QAM & 16-QAM modulation in i i d Rayleigh
fading channel. We seen that SER performance of 4x8 antennas and 4-QAM modulation scheme outperforms
others. Result shows that for higher modulation schemes SER performance degrades as well as SER
performance increases for higher no of receiver antennas
BER Performance of MU-MIMO System using Dirty Paper CodingIJEEE
In this paper Dirty Paper Coding for communication system is implemented. MIMO application that involves devices such as cell phones, pocket PCs require closely spaced antenna, which suffers from mutual coupling among antennas and high spatial correlation for signals. DPC is used for compensating the degradation due to correlation and mutual coupling.
MODIFIED LLL ALGORITHM WITH SHIFTED START COLUMN FOR COMPLEXITY REDUCTIONijwmn
Multiple-input multiple-output (MIMO) systems are playing an important role in the recent wireless
communication. The complexity of the different systems models challenge different researches to get a good
complexity to performance balance. Lattices Reduction Techniques and Lenstra-Lenstra-Lovàsz (LLL)
algorithm bring more resources to investigate and can contribute to the complexity reduction purposes.
In this paper, we are looking to modify the LLL algorithm to reduce the computation operations by
exploiting the structure of the upper triangular matrix without “big” performance degradation. Basically,
the first columns of the upper triangular matrix contain many zeroes, so the algorithm will perform several
operations with very limited income. We are presenting a performance and complexity study and our
proposal show that we can gain in term of complexity while the performance results remains almost the
same.
BER ANALYSIS FOR DOWNLINK MIMO-NOMA SYSTEMS OVER RAYLEIGH FADING CHANNELSIJCNCJournal
The Multiple-input multiple-output (MIMO) technique combined with non-orthogonal multiple access (NOMA) has been considered to enhance total system performance. This paper studies the bit error rate of two-user power-domain NOMA systems using successive interference cancellation receivers, with zeroforcing equalization over quasi-static Rayleigh fading channels. Successive interference cancellation technique at NOMA receivers has been the popular research topic due to its simple implementation, despite its vulnerability to error propagation. Closed-form expressions are derived for downlink NOMA in single-input single-output and uncorrelated quasi-static MIMO Rayleigh fading channel. Analytical results are consolidated with Monte Carlo simulation.
Bit Error Rate Performance of MIMO Spatial Multiplexing with MPSK Modulation ...ijsrd.com
Wireless communication is one of the most effective areas of technology development of our time. Wireless communications today covers a very wide array of applications. In this, we study the performance of general MIMO system, the general V-BLAST architecture with MPSK Modulation in Rayleigh fading channels. Based on bit error rate, we show the performance of the 2x2 schemes with MPSK Modulation in noisy environment. We also show the bit error rate performance of 2x2, 3x3, 4x4 systems with BPSK modulation. We see that the bit error rate performance of 2x2 systems with QPSK modulation gives us the best performance among other schemes analysed here.
Performance Analysis of Various Symbol Detection Techniques in Wireless MIMO ...IOSR Journals
Wireless communication is one of the most effective areas of technology development of our time.
Wireless communications today covers a very wide array of applications. In this paper, we study the
performance of general MIMO system, the performance of Zero Forcing (ZF), Linear Least Square Estimator
(LLSE), V-BLAST/ZF, V-BLAST/LLSE of 4x4, 4x6 & 4x8 with 4-QAM & 16-QAM modulation in i i d Rayleigh
fading channel. We seen that SER performance of 4x8 antennas and 4-QAM modulation scheme outperforms
others. Result shows that for higher modulation schemes SER performance degrades as well as SER
performance increases for higher no of receiver antennas
BER Performance of MU-MIMO System using Dirty Paper CodingIJEEE
In this paper Dirty Paper Coding for communication system is implemented. MIMO application that involves devices such as cell phones, pocket PCs require closely spaced antenna, which suffers from mutual coupling among antennas and high spatial correlation for signals. DPC is used for compensating the degradation due to correlation and mutual coupling.
MODIFIED LLL ALGORITHM WITH SHIFTED START COLUMN FOR COMPLEXITY REDUCTIONijwmn
Multiple-input multiple-output (MIMO) systems are playing an important role in the recent wireless
communication. The complexity of the different systems models challenge different researches to get a good
complexity to performance balance. Lattices Reduction Techniques and Lenstra-Lenstra-Lovàsz (LLL)
algorithm bring more resources to investigate and can contribute to the complexity reduction purposes.
In this paper, we are looking to modify the LLL algorithm to reduce the computation operations by
exploiting the structure of the upper triangular matrix without “big” performance degradation. Basically,
the first columns of the upper triangular matrix contain many zeroes, so the algorithm will perform several
operations with very limited income. We are presenting a performance and complexity study and our
proposal show that we can gain in term of complexity while the performance results remains almost the
same.
BER ANALYSIS FOR DOWNLINK MIMO-NOMA SYSTEMS OVER RAYLEIGH FADING CHANNELSIJCNCJournal
The Multiple-input multiple-output (MIMO) technique combined with non-orthogonal multiple access (NOMA) has been considered to enhance total system performance. This paper studies the bit error rate of two-user power-domain NOMA systems using successive interference cancellation receivers, with zeroforcing equalization over quasi-static Rayleigh fading channels. Successive interference cancellation technique at NOMA receivers has been the popular research topic due to its simple implementation, despite its vulnerability to error propagation. Closed-form expressions are derived for downlink NOMA in single-input single-output and uncorrelated quasi-static MIMO Rayleigh fading channel. Analytical results are consolidated with Monte Carlo simulation.
A SEMI BLIND CHANNEL ESTIMATION METHOD BASED ON HYBRID NEURAL NETWORKS FOR UP...ijwmn
The paper describes how to improve channel estimation in Single Carrier Frequency Division Multiple
Access (SC-FDMA) system, using a Hybrid Artificial Neural Networks (HANN). The 3rd Generation
Partnership Project (3GPP) standards for uplink Long Term Evolution Advanced (LTE-A) uses pilot based
channel estimation technique. This kind of channel estimation method suffers from a considerable loss
ofbitrate due to pilot insertion; all data frame sent contains reference signal. The HANN converts data
aided channel estimator to semi blind channel estimator. To increase convergence speed, HANN uses some
channel propagation Fuzzy Rules to initialize Neural Network parameters before learning instead of a
random initialization, so its learning phase ismore rapidly compared to classic ANN.HANN allows more
bandwidth efficient and less complexity. Simulation results show that HANN has better computational
efficiency than the Minimum Mean Square Error (MMSE) estimator and has faster convergence than
classic Neural Networks estimators.
ICI and PAPR enhancement in MIMO-OFDM system using RNS codingIJECEIAES
The Inter-Carrier-Interference (ICI) is considered a bottleneck in the utilization of Multiple-Input-Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems, due to the sensitivity of the OFDM towards frequency offsets which lead to loss of orthogonality, interference and performance degradation. In this paper Residue Numbers as a coding scheme is impeded in MIMO-OFDM systems, where the ICI levels is measured and evaluated with respect to conventional ICI mitigation techniques implemented in MIMO-OFDM. The Carrier-to-Interference Ratio (CIR), the system Bit-Error-Rate (BER) and the Complementary Cumulative Distribution Function (CCDF) for MIMO-OFDM system with Residue Number System (RNS) coding are analyzed and evaluated. The results had demonstrated a performance of transmission model with and without RNS.
BER Performance of MPSK and MQAM in 2x2 Almouti MIMO Systemsijistjournal
Almouti published the error performance of the 2x2 space-time transmit diversity scheme using BPSK. One of the key techniques employed for correcting such errors is the Quadrature amplitude modulation (QAM) because of its efficiency in power and bandwidth.. In this paper we explore the error performance of the 2x2 MIMO system using the Almouti space-time codes for higher order PSK and M-ary QAM. MATLAB was used to simulate the system; assuming slow fading Rayleigh channel and additive white Gaussian noise. The simulated performance curves were compared and evaluated with theoretical curves obtained using BER tool on the MATLAB by setting parameters for random generators. The results shows that the technique used do find a place in correcting error rates of QAM system of higher modulation schemes. The model can equally be used not only for the criteria of adaptive modulation but for a platform to design other modulation systems as well.
Influence of channel fading correlation on performance of detector algorithms...csandit
This paper analyzes the impact of fading correlation and cross polarization coupling on the
error performance of V-BLAST MIMO system that employs detector algorithms like ZF, MMSE
and ML with ordering and successive cancellation. Simulation results show the BER
performance of these detectors for different modulation schemes. It is observed that lesser the
channel fading correlation and cross polarization coupling values better is the performance of
these detectors. Study is extended to see the effect of transmit and receive antenna correlation
on Ergodic MIMO capacity.
NEW BER ANALYSIS OF OFDM SYSTEM OVER NAKAGAMI-n (RICE) FADING CHANNELijcseit
Modern wireless communication systems support high speed multimedia services. These services require
high data rates with acceptable error rates. Orthogonal Frequency Division Multiplexing (OFDM) is a
capable candidate to solve this problem. In this paper, a new expression for the BER of OFDM system has
been derived over Nakagami–n (Rice) fading channels using characteristics function (CHF) approach. The
exact probability density function of first order of Nakagami-n (Rice) random vector is used to derive the
expression for the error rates of OFDM system. The BER derivation of Rician fading channel is slightly
more complex compared to the Nakagami–m distribution because the PDF of the Rician RV contains an
explicit term of a modified Bessel function of first kind. Earlier, this problem was solved by replacing the
Bessel function with its infinite series and exponential integral representation. Here we propose an integral
expression to remove the complexity of the expression.
Joint impacts of relaying scheme and wireless power transfer in multiple acce...journalBEEI
This paper considers ergodic capacity of energy harvesting (EH) based cellular networks. Such a network employs non-orthogonal multiple access (NOMA) together with relaying scheme to serve two far users. In this system model, relay is facilitated power splitting (PS) protocol to implement energy harvesting (EH). To examine capacity, expressions of signal to noise ratio (SNR) need be computed to achieve capacity. Power allocation factors are different for two users in such system and hence performance gap happens to distinguish requirements for separated users. It can be confirmed that the proposed paradigm exhibits maximal achievable capacity in some scenarios of setting parameters. To confirm exactness of the analytical expressions and show advantages of the proposed EH-NOMA, simulation results are performed in terms of ergodic capacity.
Lantiq/Intel Contributions to G.fast at Scientific ConferencesLantiq
Rainer Strobel (Lantiq - An Intel Company), Michael Joham and Wolfgang Utschick presented several articles in academic conferences together with the Technical University of Munich. A conference recently held (June 8 to 12) was the ICC (International Conference on Communications) in London.
Title: Achievable Rates with Implementation Limitations for G.fast-based Hybrid Copper/Fiber Networks
Abstract - Hybrid copper/fiber networks bridge the gap between the fiber link and the customer by using copper wires over the last meters. This solution combines energy efficiency and low cost of the copper access network with high data rates of a fiber connection. However, the fiber to the distribution point (FTTdp) network must prove its ability to convey data at fiber speed over copper wire bundles under the spectral constraints of the copper access network. This work investigates achievable data rates of the FTTdp network. It provides an analysis of the sources of performance loss in a system implementation due to complexity limitations. The results indicate that optimized linear methods perform well on shorter lines, while nonlinear methods have advantages for long lines.
Capsulization of Existing Space Time TechniquesIJEEE
In this paper, we explore the fundamental
concepts behind the emerging field of space-time coding for
wireless communication system. A space–time code (STC)
is a method which employed to increase the reliability of
data transmission in the wireless communication
systems using multiple transmit antennas.
Rabid Euclidean direction search algorithm for various adaptive array geometriesjournalBEEI
One of the exciting technologies used to meet the increasing demand for wireless communication services is a smart antenna. A smart antenna is basically confirmed by an array of antennas and a digital beamformer unit through which cellular base station can direct the beam toward the desired user and set nulls toward interfering users. In this paper, different array configurations (linear, circular, and planer) with the REDS algorithm are implemented in the digital beam-forming unit. The wireless system performance is investigated to check the smart antenna potentials assuming Rayleigh fading channel environment beside the AWGN channel. Results show how the REDS algorithm offers a significant improvement through antenna radiation pattern optimization, sidelobe level, and interference reduction, and also the RDES algorithm proves fast convergence with minimum MSE and better sidelobe level reduction comparing with other algorithms.
A novel and efficient mixed-signal compressed sensing for wide-band cognitive...Polytechnique Montreal
In cognitive radio (CR) networks, unlicensed (cognitive) users can exploit the licensed frequency bands by using spectrum sensing techniques to identify spectrum holes. This paper proposes a distributed compressive spectrum sensing scheme, in which the modulated wide-band converter can apply compressed sensing (CS) directly to analog signals at the sub-Nyquist rate and the central fusion receives signals from multiple CRs and exploits the multiple-measurements-vectors (MMV) subspace pursuit (M-SP) algorithm to jointly reconstruct the spectral support of the wide-band signal. This support is then used to detect whether the licensed bands are occupy or not. Finally, extensive simulation results show the advantages of the proposed scheme. Besides, we also compare the performance of M-SP with M-orthogonal matching pursuit (M-OMP) algorithms.
Reduction of PAPR and Efficient detection ordering scheme for MIMO Transmissi...IJERA Editor
The technical challenges for communication engineers is the development of best performance wireless
networks with negligible amount of distortions. We have to consider multipath propagation attenuation and
radio spectrum inefficiency. Now a days, In MIMO (Multi Input Multi Output) systems there is a huge demand
for the networks with the high transmission rates and better quality of service which are having low PAPR ratio.
Instead of OFDMA, filter banks are used in massive MIMO to reduce the complexity. But they are error prone
to noise. This base paper discusses about PAPR reduction in MIMO systems using different precoding based
OFDM systems. Mainly, minimization of multi-antenna systems by controlling the transmission power and
reduction of PAPR using ZC (Zadoff-Chu) matrix transform.
MIMO Channel Estimation Using the LS and MMSE AlgorithmIOSRJECE
Wireless Communication Technology has developed over the past few yearsfor other objectives.The Multiple InputMultiple Output (MIMO) is one of techniques that is used to enhancethe data rates, in which multiple antennas are employed both the transmitter and receiver. Multiple signals are transmitted from different antennas at the transmitter using the same frequency and separated space. Various channel estimation techniques are employed in order to judge the physical effects of the medium present. In this paper, we analyze and implementvarious estimation techniques for MIMO Systems such as Least Squares (LS), Minimum Mean Square Error (MMSE),these techniques are therefore compared to effectively estimate the channel in MIMO System. The results demonstrate that SNR required to support different values of bit error rate varies depending on different low correlation between the transmitting and the receiving antennas .In addition, it is illustrated that when the number of transmitter and receiver antennas increases, the performance of TBCE schemes significantly improves. The Same behavior isalso observed for MIMO system. Performance of both MMSE and LSestimation are the same for allkinds of modulation at small value of SNR but the more we increase the SNR value the more performance gap goes on increasing.
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.
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile
communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by
using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on
quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s
performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant
minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) .
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
Abstract: MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) . Keywords— Adaptive modulation ASTC code, Capacity, BER, Ergodic capacity, PAPR, Spectral Efficiency and SNR
Hybrid Low Complex near Optimal Detector for Spatial Modulation IJECEIAES
In our previous work maximum throughput in multi stream MIMO is analyzed by overcoming the inter antenna interference. To mitigate the Inter antenna interference spatial modulation can be used. Spatial Modulation (SM) aided MIMO systems are the emerging MIMO systems which are low complex and energy efficient. These systems additionally use spatial dimensions for transmitting information. In this paper a low complex detector based on matched filter is proposed for spatial modulation to achieve near maximum likelihood performance while avoiding exhaustive ML search since MF based detector exhibits a considerable reduced complexity since activated transmitting antenna and modulated amplitude phase modulation constellation are estimated separately. Simulation results show the performance of the proposed method with optimal ML detector, MRC and conventional matched filter methods.
A SEMI BLIND CHANNEL ESTIMATION METHOD BASED ON HYBRID NEURAL NETWORKS FOR UP...ijwmn
The paper describes how to improve channel estimation in Single Carrier Frequency Division Multiple
Access (SC-FDMA) system, using a Hybrid Artificial Neural Networks (HANN). The 3rd Generation
Partnership Project (3GPP) standards for uplink Long Term Evolution Advanced (LTE-A) uses pilot based
channel estimation technique. This kind of channel estimation method suffers from a considerable loss
ofbitrate due to pilot insertion; all data frame sent contains reference signal. The HANN converts data
aided channel estimator to semi blind channel estimator. To increase convergence speed, HANN uses some
channel propagation Fuzzy Rules to initialize Neural Network parameters before learning instead of a
random initialization, so its learning phase ismore rapidly compared to classic ANN.HANN allows more
bandwidth efficient and less complexity. Simulation results show that HANN has better computational
efficiency than the Minimum Mean Square Error (MMSE) estimator and has faster convergence than
classic Neural Networks estimators.
ICI and PAPR enhancement in MIMO-OFDM system using RNS codingIJECEIAES
The Inter-Carrier-Interference (ICI) is considered a bottleneck in the utilization of Multiple-Input-Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) systems, due to the sensitivity of the OFDM towards frequency offsets which lead to loss of orthogonality, interference and performance degradation. In this paper Residue Numbers as a coding scheme is impeded in MIMO-OFDM systems, where the ICI levels is measured and evaluated with respect to conventional ICI mitigation techniques implemented in MIMO-OFDM. The Carrier-to-Interference Ratio (CIR), the system Bit-Error-Rate (BER) and the Complementary Cumulative Distribution Function (CCDF) for MIMO-OFDM system with Residue Number System (RNS) coding are analyzed and evaluated. The results had demonstrated a performance of transmission model with and without RNS.
BER Performance of MPSK and MQAM in 2x2 Almouti MIMO Systemsijistjournal
Almouti published the error performance of the 2x2 space-time transmit diversity scheme using BPSK. One of the key techniques employed for correcting such errors is the Quadrature amplitude modulation (QAM) because of its efficiency in power and bandwidth.. In this paper we explore the error performance of the 2x2 MIMO system using the Almouti space-time codes for higher order PSK and M-ary QAM. MATLAB was used to simulate the system; assuming slow fading Rayleigh channel and additive white Gaussian noise. The simulated performance curves were compared and evaluated with theoretical curves obtained using BER tool on the MATLAB by setting parameters for random generators. The results shows that the technique used do find a place in correcting error rates of QAM system of higher modulation schemes. The model can equally be used not only for the criteria of adaptive modulation but for a platform to design other modulation systems as well.
Influence of channel fading correlation on performance of detector algorithms...csandit
This paper analyzes the impact of fading correlation and cross polarization coupling on the
error performance of V-BLAST MIMO system that employs detector algorithms like ZF, MMSE
and ML with ordering and successive cancellation. Simulation results show the BER
performance of these detectors for different modulation schemes. It is observed that lesser the
channel fading correlation and cross polarization coupling values better is the performance of
these detectors. Study is extended to see the effect of transmit and receive antenna correlation
on Ergodic MIMO capacity.
NEW BER ANALYSIS OF OFDM SYSTEM OVER NAKAGAMI-n (RICE) FADING CHANNELijcseit
Modern wireless communication systems support high speed multimedia services. These services require
high data rates with acceptable error rates. Orthogonal Frequency Division Multiplexing (OFDM) is a
capable candidate to solve this problem. In this paper, a new expression for the BER of OFDM system has
been derived over Nakagami–n (Rice) fading channels using characteristics function (CHF) approach. The
exact probability density function of first order of Nakagami-n (Rice) random vector is used to derive the
expression for the error rates of OFDM system. The BER derivation of Rician fading channel is slightly
more complex compared to the Nakagami–m distribution because the PDF of the Rician RV contains an
explicit term of a modified Bessel function of first kind. Earlier, this problem was solved by replacing the
Bessel function with its infinite series and exponential integral representation. Here we propose an integral
expression to remove the complexity of the expression.
Joint impacts of relaying scheme and wireless power transfer in multiple acce...journalBEEI
This paper considers ergodic capacity of energy harvesting (EH) based cellular networks. Such a network employs non-orthogonal multiple access (NOMA) together with relaying scheme to serve two far users. In this system model, relay is facilitated power splitting (PS) protocol to implement energy harvesting (EH). To examine capacity, expressions of signal to noise ratio (SNR) need be computed to achieve capacity. Power allocation factors are different for two users in such system and hence performance gap happens to distinguish requirements for separated users. It can be confirmed that the proposed paradigm exhibits maximal achievable capacity in some scenarios of setting parameters. To confirm exactness of the analytical expressions and show advantages of the proposed EH-NOMA, simulation results are performed in terms of ergodic capacity.
Lantiq/Intel Contributions to G.fast at Scientific ConferencesLantiq
Rainer Strobel (Lantiq - An Intel Company), Michael Joham and Wolfgang Utschick presented several articles in academic conferences together with the Technical University of Munich. A conference recently held (June 8 to 12) was the ICC (International Conference on Communications) in London.
Title: Achievable Rates with Implementation Limitations for G.fast-based Hybrid Copper/Fiber Networks
Abstract - Hybrid copper/fiber networks bridge the gap between the fiber link and the customer by using copper wires over the last meters. This solution combines energy efficiency and low cost of the copper access network with high data rates of a fiber connection. However, the fiber to the distribution point (FTTdp) network must prove its ability to convey data at fiber speed over copper wire bundles under the spectral constraints of the copper access network. This work investigates achievable data rates of the FTTdp network. It provides an analysis of the sources of performance loss in a system implementation due to complexity limitations. The results indicate that optimized linear methods perform well on shorter lines, while nonlinear methods have advantages for long lines.
Capsulization of Existing Space Time TechniquesIJEEE
In this paper, we explore the fundamental
concepts behind the emerging field of space-time coding for
wireless communication system. A space–time code (STC)
is a method which employed to increase the reliability of
data transmission in the wireless communication
systems using multiple transmit antennas.
Rabid Euclidean direction search algorithm for various adaptive array geometriesjournalBEEI
One of the exciting technologies used to meet the increasing demand for wireless communication services is a smart antenna. A smart antenna is basically confirmed by an array of antennas and a digital beamformer unit through which cellular base station can direct the beam toward the desired user and set nulls toward interfering users. In this paper, different array configurations (linear, circular, and planer) with the REDS algorithm are implemented in the digital beam-forming unit. The wireless system performance is investigated to check the smart antenna potentials assuming Rayleigh fading channel environment beside the AWGN channel. Results show how the REDS algorithm offers a significant improvement through antenna radiation pattern optimization, sidelobe level, and interference reduction, and also the RDES algorithm proves fast convergence with minimum MSE and better sidelobe level reduction comparing with other algorithms.
A novel and efficient mixed-signal compressed sensing for wide-band cognitive...Polytechnique Montreal
In cognitive radio (CR) networks, unlicensed (cognitive) users can exploit the licensed frequency bands by using spectrum sensing techniques to identify spectrum holes. This paper proposes a distributed compressive spectrum sensing scheme, in which the modulated wide-band converter can apply compressed sensing (CS) directly to analog signals at the sub-Nyquist rate and the central fusion receives signals from multiple CRs and exploits the multiple-measurements-vectors (MMV) subspace pursuit (M-SP) algorithm to jointly reconstruct the spectral support of the wide-band signal. This support is then used to detect whether the licensed bands are occupy or not. Finally, extensive simulation results show the advantages of the proposed scheme. Besides, we also compare the performance of M-SP with M-orthogonal matching pursuit (M-OMP) algorithms.
Reduction of PAPR and Efficient detection ordering scheme for MIMO Transmissi...IJERA Editor
The technical challenges for communication engineers is the development of best performance wireless
networks with negligible amount of distortions. We have to consider multipath propagation attenuation and
radio spectrum inefficiency. Now a days, In MIMO (Multi Input Multi Output) systems there is a huge demand
for the networks with the high transmission rates and better quality of service which are having low PAPR ratio.
Instead of OFDMA, filter banks are used in massive MIMO to reduce the complexity. But they are error prone
to noise. This base paper discusses about PAPR reduction in MIMO systems using different precoding based
OFDM systems. Mainly, minimization of multi-antenna systems by controlling the transmission power and
reduction of PAPR using ZC (Zadoff-Chu) matrix transform.
MIMO Channel Estimation Using the LS and MMSE AlgorithmIOSRJECE
Wireless Communication Technology has developed over the past few yearsfor other objectives.The Multiple InputMultiple Output (MIMO) is one of techniques that is used to enhancethe data rates, in which multiple antennas are employed both the transmitter and receiver. Multiple signals are transmitted from different antennas at the transmitter using the same frequency and separated space. Various channel estimation techniques are employed in order to judge the physical effects of the medium present. In this paper, we analyze and implementvarious estimation techniques for MIMO Systems such as Least Squares (LS), Minimum Mean Square Error (MMSE),these techniques are therefore compared to effectively estimate the channel in MIMO System. The results demonstrate that SNR required to support different values of bit error rate varies depending on different low correlation between the transmitting and the receiving antennas .In addition, it is illustrated that when the number of transmitter and receiver antennas increases, the performance of TBCE schemes significantly improves. The Same behavior isalso observed for MIMO system. Performance of both MMSE and LSestimation are the same for allkinds of modulation at small value of SNR but the more we increase the SNR value the more performance gap goes on increasing.
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.
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile
communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by
using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on
quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s
performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant
minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) .
Capacity Enhancement of MIMO-OFDM System in Rayleigh Fading ChannelIOSR Journals
Abstract: MIMO-OFDM system in Rayleigh Fading Channel is very popular technique for mobile communication now a day’s for research. Here we want increase the capacity of MIMO-OFDM of system by using adaptive modulation, Algebraic Space-Time Codes (ASTC) encoder for MIMO Systems are based on quaternion algebras .we found that ergodic capacity has some limitation which reduce the system’s performance to overcome this we use ASTC code . ASTC code are full rank, full rate and non vanishing constant minimum determinant for increasing spectral efficiency and reducing Peak to Average Power Ratio (PAPR) . Keywords— Adaptive modulation ASTC code, Capacity, BER, Ergodic capacity, PAPR, Spectral Efficiency and SNR
Hybrid Low Complex near Optimal Detector for Spatial Modulation IJECEIAES
In our previous work maximum throughput in multi stream MIMO is analyzed by overcoming the inter antenna interference. To mitigate the Inter antenna interference spatial modulation can be used. Spatial Modulation (SM) aided MIMO systems are the emerging MIMO systems which are low complex and energy efficient. These systems additionally use spatial dimensions for transmitting information. In this paper a low complex detector based on matched filter is proposed for spatial modulation to achieve near maximum likelihood performance while avoiding exhaustive ML search since MF based detector exhibits a considerable reduced complexity since activated transmitting antenna and modulated amplitude phase modulation constellation are estimated separately. Simulation results show the performance of the proposed method with optimal ML detector, MRC and conventional matched filter methods.
IMPROVEMENT OF LTE DOWNLINK SYSTEM PERFORMANCES USING THE LAGRANGE POLYNOMIAL...IJCNCJournal
To achieve a high speed data rate, higher spectral efficiency, improved services and low latency the 3rd
generation partnership project designed LTE standard (Long Term Evolution).the LTE system employs
specific technical as well the technical HARQ, MIMO transmission, OFDM Access or estimation technical.
In this paper we focus our study on downlink LTE channel estimation and specially the interpolation which
is the basis of the estimation of the channel coefficients. Thus, we propose an adaptive method for polynomial interpolation based on Lagrange polynomial. We perform the Downlink LTE system MIMO transmission then compare the obtained results with linear, Sinus Cardinal and polynomial Newton Interpolations. The simulation results show that the Lagrange method outperforms system performance in term of Block Error Rate (BLER) , throughput and EVN(%)vs. Signal to Noise Ratio (SNR).
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.
Singular Value Decomposition: Principles and Applications in Multiple Input M...IJCNCJournal
The authors discuss the importance of using the singular value decomposition (SVD) in computing the capacity of multiple input multiple output (MIMO) and in estimation the channel gain from the transmitter to the receiver. Examples that show how the SVD simplifies computing the MIMO channel capacity are discussed. Numerical results that show what factors determine the performance of using SVD in channel
estimation are also discussed.
Analysis of Space Time Codes Using Modulation TechniquesIOSR Journals
Abstract: In this Paper, Analysis of channel codes for improving the data rate and reliability of communication over fading channels using multiple transmit antennas has been considered. The codes, namely ’Space Time Codes’ render full diversity and amend coding gain. Performance criteria for designing such codes, under this assumption that the fading is slow and nonselective frequency, is also analysed. Under this research, Study of Frame Error Rate(FER) and outage capacity is compared for different no. Of transmit and receive antennas as well as for different modulation techniques. According to theoretical results FER decreases with increasing SNR and No. Of receiving antennas. Numerical and practical result shows that FER decreases with increasing SNR and no. Of receiving antennas. Keywords: Space time Block Codes ,Space time trellis Codes,Frame Error Rate(FER),Outage capacity,Pairwise Error Probability
BER Analysis for Downlink MIMO-NOMA Systems over Rayleigh Fading ChannelsIJCNCJournal
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3D METALLIC PLATE LENS ANTENNA BASED BEAMSPACE CHANNEL ESTIMATION TECHNIQUE F...ijwmn
Beamspace channel estimation mechanism for massive MIMO (multiple input multiple output) antenna
system presents a major process to compensate the 5G spectrum challenges caused by the proliferation of
information from mobile devices. However, this estimation is required to ensure the perfect channel state
information (CSI) for lower amount of Radio Frequency (RF) chains for each beam. In addition, phase
shifter (PS) components used in this estimation need high power to select the beam in the desired direction.
To overcome these limitations, in this work, we propose Regular Scanning Support Detection (RSSD)
based channel estimation mechanism. Moreover, we utilise a 3D lens antenna array having metallic plate
and a switch in our model which compensates the limitation of phase shifters. Simulation results show that
the proposed RSSD based channel estimation surpasses traditional technique and SD based channel
estimation even in lower SNR area which is highly desirable in the millimeter wave (mmWave) massive
MIMO systems.
3D METALLIC PLATE LENS ANTENNA BASED BEAMSPACE CHANNEL ESTIMATION TECHNIQUE F...ijwmn
Beamspace channel estimation mechanism for massive MIMO (multiple input multiple output) antenna
system presents a major process to compensate the 5G spectrum challenges caused by the proliferation of
information from mobile devices. However, this estimation is required to ensure the perfect channel state
information (CSI) for lower amount of Radio Frequency (RF) chains for each beam. In addition, phase
shifter (PS) components used in this estimation need high power to select the beam in the desired direction.
To overcome these limitations, in this work, we propose Regular Scanning Support Detection (RSSD)
based channel estimation mechanism. Moreover, we utilise a 3D lens antenna array having metallic plate
and a switch in our model which compensates the limitation of phase shifters. Simulation results show that
the proposed RSSD based channel estimation surpasses traditional technique and SD based channel
estimation even in lower SNR area which is highly desirable in the millimeter wave (mmWave) massive
MIMO systems.
Intersymbol interference caused by multipath in band limited frequency selective time dispersive channels distorts the transmitted signal, causing bit error at receiver. ISI is the major obstacle to high speed data transmission over wireless channels. Channel estimation is a technique used to combat the intersymbol interference. The objective of this paper is to improve channel estimation accuracy in MIMO-OFDM system by using modified variable step size leaky Least Mean Square (MVSSLLMS) algorithm proposed for MIMO OFDM System. So we are going to analyze Bit Error Rate for different signal to noise ratio, also compare the proposed scheme with standard LMS channel estimation method.
Distributed Spatial Modulation based Cooperative Diversity Schemeijwmn
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wireless networks is proposed. Where, the space-time block code is exploited to integrate with distributed
spatial modulation. Therefore, the interested transmission scheme achieves high diversity gain. By using
Monte-Carlo simulation based on computer, we showed that our proposed transmission scheme outperforms
state-of-the-art cooperative relaying schemes in terms bit error rate (BER) performance.
Computationally Efficient Multi-Antenna Techniques for Multi-User Two-Way Wire...IJECEIAES
In this work, we are interested in implementing, developing and evaluating multi-antenna techniques used for multi-user two-way wireless relay networks that provide a good tradeoff between the computational complexity and performance in terms of symbol error rate and achievable data rate. In particular, a variety of newly multi-antenna techniques is proposed and studied. Some techniques based on orthogonal projection enjoy low computational complexity. However, the performance penalty associated with them is high. Other techniques based on maximum likelihood strategy enjoy high performance, however, they suffer from very high computational complexity. The Other techniques based on randomization strategy provide a good trade-off between the computational complexity and performance where they enjoy low computational complexity with almost the same performance as compared to the techniques based on maximum likelihood strategy.
Performance analysis of adaptive filter channel estimated MIMO OFDM communica...IJECEIAES
Advanced Communication Systems are wideband systems to support multiple applications such as audio, video and data so and so forth. These systems require high spectral efficiency and data rates. In addition, they should provide multipath fading and inter-symbol interference (ISI) free transmission. Multiple input multiple output orthogonal frequency division multiplexing (MIMO OFDM) meets these requirements Hence, MIMOOFDM is the most preferable technique for long term evaluation advanced (LTEA). The primary objective of this paper is to control bit error rate (BER) by proper channel coding, pilot carriers, adaptive filter channel estimation schemes and space time coding (STC). A combination of any of these schemes results in better BER performance over individual schemes. System performance is analyzed for various digital modulation schemes. In this paper, adaptive filter channel estimated MIMO OFDM system is proposed by integrating channel coding, adaptive filter channel estimation, digital modulation and space time coding. From the simulation results, channel estimated 2×2 MIMO OFDM system shows superior performance over individual schemes.
CHANNEL ESTIMATION AND MULTIUSER DETECTION IN ASYNCHRONOUS SATELLITE COMMUNIC...ijwmn
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New Adaptive Cooperative-MIMO for LTE Technologyijtsrd
Multiple Input Multiple Output (MIMO) systems have been widely used in an area of wireless cellular communication system, providing the both increased capacity and reliability. However, the use of multiple antennas in mobile terminals may not be very practical due to limited space and other implementation issues. In this paper, cooperative MIMO has been used in a way to optimise the implementation and working of conventional MIMO systems in terms of BER and Spectral Efficiency while maintaining a minimal number of antennas on each handset. Cooperative MIMO with V-BLAST transmission over Rayleigh flat fading channels and amplify and forward protocol with one relay node for modulation techniques like BPSK, QPSK, QAM using various decoding techniques has been analysed. Decoding algorithms like ZF, MMSE and ML have been analysed with respect to their BER performances. Since, there is throughput loss in cooperative MIMO due to extra resources required for relaying, adaptive modulation has been used with C-MIMO to meet the demands for high data rates in Long Term Evolution Network. Sukhreet Kaur | Dr. Amita Soni"New Adaptive Cooperative-MIMO for LTE Technology" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-4 , June 2018, URL: http://www.ijtsrd.com/papers/ijtsrd12919.pdf http://www.ijtsrd.com/engineering/electronics-and-communication-engineering/12919/new-adaptive-cooperative-mimo-for-lte-technology/sukhreet-kaur
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Keying (QPSK) and Quadrature Amplitude Modulation (QAM) with multiple antennas are measured with
respect to BER. In this paper, it is shown that Hybrid MIMO provides low BER. Thus, in wireless
communication, hybrid model improves the data rate and link reliability.
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1. International Journal of Mobile Network Communications & Telematics ( IJMNCT) Vol. 4, No.5,October 2014
PERFORMANCE EVALUATION WITH A
COMPARATIVE ANALYSIS OF MIMO CHANNEL ON
THE BASIS OF DOPPLER SHIFT AND OTHER
PROBABILISTIC PARAMETERS IN FADING
ENVIRONMENT
Sutanu Ghosh
Dr. Sudhir Chandra Sur Degree Engineering College
ABSTRACT
At this present scenario, the demand of the system capacity is very high in wireless network. MIMO
technology is used from the last decade to provide this requirement for wireless network antenna
technology. MIMO channels are mostly used for advanced antenna array technology. But it is most
important to control the error rate with enhanced system capacity in MIMO for present-day progressive
wireless communication. This paper explores the frame error rate with respect to different path gain of
MIMO channel. This work has been done in different fading scenario and produces a comparative analysis
of MIMO on the basis of those fading models in various conditions. Here, it is to be considered that
modulation technique as QPSK to observe these comparative evaluations for different Doppler frequencies.
From the comparative analysis, minimum amount of frame error rate is viewed for Rician distribution at
LOS path Doppler shift of 0 Hz. At last, this work is concluded with a comparative bit error rate study on
the basis of singular parameters at different SNR levels to produce the system performance for uncoded
QPSK modulation.
KEYWORDS
MIMO, OSTBC Encoder-Combiner, Rician, Rayleigh, correlation, MMSE, ML.
I. INTRODUCTION
Today, all the mobile users have required higher data rate with better quality of service. This
higher capacity can be reached using MIMO technology [1]. MIMO is an antenna array
technology with different correlation [2] pattern. Correlation is observed in between two different
channels. On the basis of this correlation there are three different levels – high, medium and low.
Higher amount of capacity can be achieved through low level correlation. These correlation levels
are combined with different antenna array pattern – 2X2; 4X4 or, 8X8 etc. 4X4 array pattern
means, each of the both end at transmitter and receiver side has four antennas. Specifically, 2X2
and 4X4 have less amount of correlation [3]. So, these two arrays are mostly used for the
transmission of data. In this paper, I have used 4X4 antenna array for MIMO communication
channel. Here, MIMO channel is worked with different fading model- Rayleigh fading
distribution model and Rician fading distribution model. This fading is the most considerable
issue for present day wireless communication system. Rayleigh [4] and Rician [5, 6] are very well
known statistical distribution for amplitude modeling of radio signal in fading environment. In
this research, I have worked with two different LOS path doopler shift [7] for Rician fading
DOI : 10.5121/ijmnct.2014.4503 35
2. International Journal of Mobile Network Communications & Telematics ( IJMNCT) Vol. 4, No.5,October 2014
model. Any kind of mobile communication, antenna receives a large number of reflected and
scattered waves from various directions. The instantaneous power of these received signals with
Rayleigh/ Rician distribution follows the exponential function. In this work, I have considered a
binary source to generate the information, which has been modulated by QPSK modulator. The
information symbols output of QPSK Modulator is encoded by OSTBC Encoder [8] by using
either the Alamouti code [9, 10] for two transmit antennas or other generalized complex
orthogonal codes for three or four transmit antennas. The input as number of transmit antennas is
given to the encoder and output of this encoder is an (Ns x Nt) variable-size matrix, where the
number of columns (Nt) corresponds to the number of transmit antennas and the number of rows
(Ns) corresponds to the number of orthogonal code samples transmitted over each transmit
antenna in a frame. The output of this block can be passed to the MIMO channel and finally
received at OSTBC combiner [11]. The function of this combiner is to combine the received
signal with different channel state information and to estimate the modulated symbols. The input
signal of this combiner is an (Ns x Nr) variable-size matrix. The QPSK Demodulator block
demodulates the output of OSTBC Combiner, which is a recovered modulated signal using the
quaternary phase shift keying method.
Before this work, there was little research on the basis of behavior of MIMO channel. Ref. [12]
introduced new algorithms for the construction of approximate minimum-error-rate linear MIMO
receiver. But they didn’t explain the effect of this algorithm at different level of Doppler
frequency. Ref. [13] illustrated the packet error rate for different alamouti scheme [14] or receive
diversity and symbol error rate for different antenna configuration with various realistic
parameters. But this work didn’t explain the effect of MIMO at different fading model. Ref. [15]
described only the bit error rate for different level of SNR with the help of the parameters -
maximum likelihood detection [16] and QPSK modulation. So, these works are not sufficient for
the analysis of system performance on the problem of frame error rate at different level of
Doppler frequency and different fading model. To the best of my knowledge, this kind of work
has not been done for MIMO. So, I have worked on this issue to execute a performance analysis
on the basis of a comparative graphical result.
The remaining portions of this paper are arranged as follows: Sections II and III, describes an
overview of MIMO Channel with OSTBC Encoder-Combiner and Binary data generator with
QPSK modulator-demodulator respectively. Simulation and experimental results is illustrated in
Section IV. Finally, this paper is concluded in Section V.
II. MIMO CHANNEL WITH OSTBC ENCODER AND OSTBC
COMBINER:
In this work, MIMO channel is introduced with different values of Doppler frequencies. This
MIMO technology have different types of antenna array configuration (2X2, 4X4, 8X8 etc) with
different level of correlation as shown in Figure 1. Channel correlation is an evaluation of
similarity or likeliness of two or, more different channels. There are three different correlation
levels - High, Low and Medium. Here, this MIMO channel is worked with two different fading
models. These models include Rayleigh and Rician distribution for different levels of Doppler
frequency.
36
3. International Journal of Mobile Network Communications & Telematics ( IJMNCT) Vol. 4, No.5,October 2014
Figure 1: MIMO channel antenna configuration
[a] Rayleigh model is mathematically
probability distribution function of instantaneous power of Rayleigh
exponential distribution property
[17] –
p (m) =
…(1) where,
m
0 m = E[m] = {
0
m
m
E[m] is average and 22 is mean square value.
mathematical manipulation over clarke’s reference model [18, 19]. The low pass Rayleigh fading
process [20] can be mathematically
u(t) =
N
+ Y +
= =
… ... (2)
where, i and i are angle of incoming wave and initial phase associated with i
wd is maximum angular Doppler frequency occurring when
selections of i and i are not unique
results against eq. 2.
[b] Rician, another fading model has fixed LOS component. It considers that dominant
wave can be a phasor sum of two or more dominant signals (like, ground reflection, line of sight
etc.). It is treated as a deterministic process. A sinusoid signal
Rician multipath channel can be
o(t) = c c A cosw
N
+ + Y
i c i t t
… …(3)
where, Ac is the amplitude of line of sight component (Rayleigh fading is recovered for
of Ac = 0), i is the amplitude of i
N identify the reflected and scattered wave.
over (local-mean) scattered power is defined as Rician
K =
m
c
2
2a
…(4)
If, value of K is 0 then channel is Rayleigh and
2 is local-mean scattered power and
1
m c is power of dominant component. The probability
defined as [6] –
distribution function of Rician model is de
with different path gain m11, m12, m21 and m22
expressed by Rayleigh distribution function. The
model
property. The probability distribution function of power is defined
exp( )
1
0 0
m
−
2 m.p(m)}dm = 2a
Rayleigh fading process can be illustrated from the
described as –
{ 2cos( cos ) 2cos( sin
2
1 i
1
d
N
i
d i i w t j w t
M
a
th propagation path,
i = 0. It should be characterize
unique; however, different selections will proceed
i(t) = cos(ct) received over a
characterized as –
=
i
1
a cos(w )
th reflected wave, i is the phase of ith reflected wave and i =1to
The ratio of signal power in dominant component
K-factor [6].
2
for AWGN, K is .
2
2
37
d follows the
. by
… …
+ Q )}
i i
a
characterized that
for different
… …
the value
… … …
4. International Journal of Mobile Network Communications Telematics ( IJMNCT) Vol. 4, No.5,October 2014
38
pZ(x) = exp[ ( ) / 2 ] ( )
0 2
2 2 2
a
2 a
a
m
m
xc
x c I
x
− + , x 0,
where, 22 = , ¹0
2 [ ]
i i i E s is average power in non-LOS multipath components and cm
2 = 0
2 is
power in LOS component. The function I0 is modified Bessel function of 0th order and Z =
2 2 x + y , where, x and y is two Gaussian random variable, both with mean 0 and equal
variance.
These two fading model is associated with MIMO configuration and performed with two more
blocks – OSTBC encoder [21] at transmitter and OSTBC combiner [22] at receiver side. OSTBC
Encoder block encodes input symbol sequence using orthogonal space-time block code (OSTBC).
Function of this block is to map input symbols block-wise and concatenates the output codeword
matrices in time domain. OSTBC Encoder block supports five different OSTBC encoding
algorithms on the basis of different rate and number of transmitting antennas, as shown in Table -
I. There are 5 different OSTBC codeword [23] matrix for these 5 different OSTBC encoding
algorithm.
Table –I : Symbol Rate Adaptation for Different Number of Transmit Antennas
Number of transmit
antennas
Symbol Rate
2 1
3 ½
3 ¾
4 ½
4 ¾
This encoder supports time and spatial domains for OSTBC transmission and supports also an
optional dimension; where encoding calculation is independent through that domain. This
dimension may be thought of as a frequency domain.
The received information from all different receiver antennas is combined through the OSTBC
combiner at receiving section. Input channel estimation may not be fixed during each codeword
block transmission and combining algorithm uses only an approximation for first symbol period
per codeword block. Symbol demodulator or decoder would follow Combiner block of MIMO
communications system. It supports to combine each symbol independently using the combining
algorithm depends on the structure of OSTBC. Combiner supports 5 different algorithm same as
that of encoding algorithm. Computation algorithm per codeword block length is different for 5
different algorithms.
III. BINARY DATA GENERATOR WITH QPSK MODULATOR AT
TRANSMITTER AND DEMODULATOR AT RECEIVER OF MIMO
CHANNEL
Binary data is generated by a source with Bernoulli distribution [24]. Output of this source may
be frame based or sample based. Both of these two frames or sample can be expressed through a
matrix. The output of this source is modulated by any kind of modulator. Here, I have used only
QPSK modulator at transmitter side and demodulator at receiver side. This modulator generates a
modulated symbol for every 2 successive input bits. Figure 2 depicts the total system
representation of a robust MIMO channel [25 - 27] with OSTBC encoder and combiner.
5. International Journal of Mobile Network Communications Telematics ( IJMNCT) Vol. 4, No.5,October 2014
Figure 2: Block diagram of MIMO system
IV. SIMULATION AND EXPERIMENTAL RESULTS
In this research work, I have used a set of parameters to execute the simulation.
been simulated in MATLAB. In
to propagate signal in the system
velocity is utilized to measure the radial velocity of moving object.
performance is calculated on the basis of
with signal to noise ratio. Those parameters are as follows
this simulation work, I have considered 2 or more discrete paths
and gains of these paths are computed in decibels.
d Doppler
d In this work, system
Table
This work has
frame error rate, Doppler frequency and
–
–II : SIMULATION PARAMETERS
Name of the parameters Value
Type of Antenna Array 4 X 4
Modulation type QPSK
Type of fading model Rayleigh and
Rician
LOS path Doppler shift taken as 0 and 100
Hz
The total result can be subdivided into two different categories. One includes all the frame error
rate calculations with different level of Doppler frequencies.
frame error rate for different values of sample rate.
calculations for different level probabilistic parameters.
MATLAB and validated through Qualnet 6.1 simulation software
RESULTS
Here, I have produced the results of
Next section includes the bit error rate
This work has been simulated in
[28].
In the first category, frame error rate has been calculated for three different cases and for all
those cases, discrete path delay is assumed to be 0 value. Figure 3 shows the frame error rate for
different path gain at 100 Hz
Doppler shift. The graphical comparison is done
of two
39
his bit error rate
on the basis
6. International Journal of Mobile Network Communications Telematics ( IJMNCT) Vol. 4, No.5,October 2014
Figure 3: Graphical analysis of frame error rate for different fading model at maximum Doppler shift of 100
40
Hz
different fading model. In these evaluations, I have considered two different conditions for Rician
model on the basis of LOS path Doppler shift. It is very easy to observe the lowest frame error
rate is occurred for 0 Hz Rician model.
Figure 4: Graphical analysis of frame error rate for different fading model at maximum Doppler shift of 50
Hz
7. International Journal of Mobile Network Communications Telematics ( IJMNCT) Vol. 4, No.5,October 2014
Figure 5: Graphical analysis of frame error rate for different fading model at maximum Doppler shift of 25
41
Hz
Figure 4 and 5 presents the comparative analysis at 50 and 25 Hz Doppler shift respectively. It is
very obvious that highest frame rate is observed for Rayleigh fading model. The lowest frame
error rate is viewed for LOS path Doppler shift of 100 Hz Rician fading model at 25 Hz. If the
amount of Doppler shift is increased to 50 Hz and above then lowest frame error rate is observed
for LOS path Doppler shift of 0 Hz Rician fading model. So, high frequency of Doppler shift is
better for LOS path Doppler shift of 0 Hz Rician model on the basis of frame error rate.
Figure 6: Graphical analysis of frame error rate for different values of sample rate in MIMO system
8. International Journal of Mobile Network Communications Telematics ( IJMNCT) Vol. 4, No.5,October 2014
This Figure 6 presents the graphical result of frame error rate for different values of sample rate.
This frame error rate is increased for higher values of sample rate. From initial level frame error
rate is decreased upto the value of 2X106, then it is increased sharply with the enhanced sample
rate. The minimum value of frame error rate is observed at sample rate of 2X106.
This section has described the results of bit error rate (BER) for different probabilistic variables –
maximum likelihood (ML), minimum mean square error (MMSE) for different equalization
scheme. ML is a mathematical algorithm to find the useful data from the noisy data stream.
MMSE algorithm is used to reduce the noise power. Zero forcing (ZF) equalizer applies the
inverse transfer function of the channel frequency response to received signal to bring back the
signal after the channel. Here results are compared with zero forcing equalizer output and final
comparative outcome is plotted in Figure 7. In this comparison, ML has the lowest BER with
respect to other scheme. This ML has almost 0 BER at 20 dB SNR level.
42
Figure 7: Graphical comparison for different pre-allocate variables in 4x4 uncoded QPSK system
V. CONCLUSION
This paper investigates an idea about the performance evaluation on the basis of frame error rate
for different frequency of Doppler shift in different types of fading model. I studied that frame
error rate for Rayleigh fading is almost same for three different Doppler frequency shift (25, 50
and 100 Hz) of my experiment. From the experimental result, it can be concluded that Rician
fading channel is far better than Rayleigh fading channel for the reduction of frame error rate. If
the velocity of mobile object is increased at that time Rician model is performed superior than
Rayleigh model.
I have produced another result for bit error rate at 4X4 system. From this result, it is proved that
bit error rate is lowest and system performance is stabilized at high level of SNR for ML
equalization method. The comparative result of this paper will serve a great future path for further
research work.
9. International Journal of Mobile Network Communications Telematics ( IJMNCT) Vol. 4, No.5,October 2014
43
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