This document discusses matrix inversion techniques for MIMO wireless communication systems. It begins by introducing how matrix inversion is used in algorithms for MIMO systems and standards like 802.11n. Existing matrix inversion approaches cannot achieve the performance needed for real-time 802.11n systems. The document then presents a new matrix inversion algorithm based on modified squared Givens rotations (MSGR) that enables real-time implementation with high throughput and low latency. This algorithm overcomes limitations of other QR decomposition techniques. Finally, the document evaluates this algorithm integrated into a MIMO receiver and demonstrates it can support the requirements of modern wireless standards like 802.11n.
A simulation model of ieee 802.15.4 in om ne t++wissem hammouda
This document presents a simulation model of the IEEE 802.15.4 standard developed in OMNeT++. The model consists of PHY, MAC and traffic modules. The PHY module implements radio states, CCA and data rates according to the standard. The MAC module implements CSMA-CA, beaconing, data transmission modes and a simple energy model. The traffic module generates packets. The model supports star and cluster tree topologies and allows configuring parameters to evaluate IEEE 802.15.4 performance.
A New Approach to Linear Estimation Problem in Multiuser Massive MIMO SystemsRadita Apriana
A novel approach for solving linear estimation problem in multi-user massive MIMO systems is
proposed. In this approach, the difficulty of matrix inversion is attributed to the incomplete definition of the
dot product. The general definition of dot product implies that the columns of channel matrix are always
orthogonal whereas, in practice, they may be not. If the latter information can be incorporated into dot
product, then the unknowns can be directly computed from projections without inverting the channel
matrix. By doing so, the proposed method is able to achieve an exact solution with a 25% reduction in
computational complexity as compared to the QR method. Proposed method is stable, offers an extra
flexibility of computing any single unknown, and can be implemented in just twelve lines of code.
11 construction productivity and cost estimation using artificial Vivan17
This chapter discusses using artificial neural networks (ANNs) to estimate construction project productivity and costs. ANNs can learn from previous examples to predict outputs like cost and schedule based on input data. The chapter provides an overview of ANNs and examples of their use in construction cost and duration estimation. It then presents a framework for developing ANNs for productivity and cost predictions, and provides a detailed case study applying ANNs to estimate productivity of precast installation activities. The case study ANN was able to predict installation times with an average error of around 20%, demonstrating the potential of ANNs for aiding construction cost and schedule estimates.
This document proposes two genetic algorithm based methodologies called Minimum Spanning Tree First (MSTF) and Shortest Paths First (SPF) for designing customized and energy optimized irregular Network-on-Chip (NoC) topologies tailored to an application's communication characteristics. The MSTF methodology first constructs a minimum spanning tree and then extends the topology by adding shortest energy paths, while SPF first finds the shortest energy paths and then constructs the minimum spanning tree. Experimental results on random benchmarks show the SPF methodology reduces average dynamic communication energy by 18.5% on average compared to MSTF. SPF also achieves lower latency and similar throughput. Comparisons with regular 2D mesh NoCs and an intelligent mapping
Application of MUSIC Algorithm for Adaptive Beamforming Smart AntennaIRJET Journal
This document discusses direction of arrival (DOA) estimation using the MUSIC algorithm. It begins with an abstract that introduces DOA estimation and the MUSIC algorithm. It then provides background on smart antennas and switched beam arrays. The document presents the system model and mathematical formulation for signal propagation and antenna array output. It then describes the MUSIC algorithm, which uses eigendecomposition of the covariance matrix to estimate DOA. The algorithm is able to simultaneously measure multiple signals with high precision and resolution. The document concludes by discussing implementation of the algorithm using a 4-element antenna array to estimate DOA.
BER Performance of MPSK and MQAM in 2x2 Almouti MIMO Systemsijistjournal
This document summarizes the results of simulations comparing the bit error rate (BER) performance of different modulation schemes in a 2x2 MIMO system using Almouti space-time coding. The key findings are:
1) Higher order modulation schemes like QPSK, 16-QAM, and 64-QAM require more energy (i.e. higher Eb/No ratio) than lower order schemes like BPSK to achieve the same BER performance.
2) 16-QAM requires less energy than 16-PSK to achieve the same BER, since QAM signal points are distributed without being confined to a circle like PSK.
3) Simulated BER performance matches theoretical curves closely for Q
IRJET- Study of MIMO Precoding Techniques and their Application using Joi...IRJET Journal
This document discusses a study of MIMO precoding techniques and their application using joint spatial-division and multiplexing (JSDM) to address challenges in frequency-division duplex massive MIMO systems. It proposes a two-tier precoding approach with an outer precoder to mitigate inter-cluster interference based on statistical channel information and an inner precoder to spatially multiplex intra-cluster users. This approach reduces overhead and complexity compared to conventional techniques by exploiting channel correlations between users within clusters. The document also derives an iterative algorithm to track the outer precoder online and analyzes its tracking performance over time-varying channels.
Application of smart antenna interference suppression techniques in tdscdmamarwaeng
This document discusses the application of smart antenna interference suppression techniques in TD-SCDMA systems. It first provides background on TD-SCDMA and smart antenna technology. It then describes two adaptive beamforming algorithms - LMS and RLS - and simulates their performance at interference suppression in MATLAB. The simulation results show that both algorithms can effectively form a main beam towards the desired user and nulls towards interferers. RLS converges faster than LMS, though it has higher computational complexity. The study demonstrates that smart antenna techniques can improve signal quality in TD-SCDMA systems by suppressing interference.
A simulation model of ieee 802.15.4 in om ne t++wissem hammouda
This document presents a simulation model of the IEEE 802.15.4 standard developed in OMNeT++. The model consists of PHY, MAC and traffic modules. The PHY module implements radio states, CCA and data rates according to the standard. The MAC module implements CSMA-CA, beaconing, data transmission modes and a simple energy model. The traffic module generates packets. The model supports star and cluster tree topologies and allows configuring parameters to evaluate IEEE 802.15.4 performance.
A New Approach to Linear Estimation Problem in Multiuser Massive MIMO SystemsRadita Apriana
A novel approach for solving linear estimation problem in multi-user massive MIMO systems is
proposed. In this approach, the difficulty of matrix inversion is attributed to the incomplete definition of the
dot product. The general definition of dot product implies that the columns of channel matrix are always
orthogonal whereas, in practice, they may be not. If the latter information can be incorporated into dot
product, then the unknowns can be directly computed from projections without inverting the channel
matrix. By doing so, the proposed method is able to achieve an exact solution with a 25% reduction in
computational complexity as compared to the QR method. Proposed method is stable, offers an extra
flexibility of computing any single unknown, and can be implemented in just twelve lines of code.
11 construction productivity and cost estimation using artificial Vivan17
This chapter discusses using artificial neural networks (ANNs) to estimate construction project productivity and costs. ANNs can learn from previous examples to predict outputs like cost and schedule based on input data. The chapter provides an overview of ANNs and examples of their use in construction cost and duration estimation. It then presents a framework for developing ANNs for productivity and cost predictions, and provides a detailed case study applying ANNs to estimate productivity of precast installation activities. The case study ANN was able to predict installation times with an average error of around 20%, demonstrating the potential of ANNs for aiding construction cost and schedule estimates.
This document proposes two genetic algorithm based methodologies called Minimum Spanning Tree First (MSTF) and Shortest Paths First (SPF) for designing customized and energy optimized irregular Network-on-Chip (NoC) topologies tailored to an application's communication characteristics. The MSTF methodology first constructs a minimum spanning tree and then extends the topology by adding shortest energy paths, while SPF first finds the shortest energy paths and then constructs the minimum spanning tree. Experimental results on random benchmarks show the SPF methodology reduces average dynamic communication energy by 18.5% on average compared to MSTF. SPF also achieves lower latency and similar throughput. Comparisons with regular 2D mesh NoCs and an intelligent mapping
Application of MUSIC Algorithm for Adaptive Beamforming Smart AntennaIRJET Journal
This document discusses direction of arrival (DOA) estimation using the MUSIC algorithm. It begins with an abstract that introduces DOA estimation and the MUSIC algorithm. It then provides background on smart antennas and switched beam arrays. The document presents the system model and mathematical formulation for signal propagation and antenna array output. It then describes the MUSIC algorithm, which uses eigendecomposition of the covariance matrix to estimate DOA. The algorithm is able to simultaneously measure multiple signals with high precision and resolution. The document concludes by discussing implementation of the algorithm using a 4-element antenna array to estimate DOA.
BER Performance of MPSK and MQAM in 2x2 Almouti MIMO Systemsijistjournal
This document summarizes the results of simulations comparing the bit error rate (BER) performance of different modulation schemes in a 2x2 MIMO system using Almouti space-time coding. The key findings are:
1) Higher order modulation schemes like QPSK, 16-QAM, and 64-QAM require more energy (i.e. higher Eb/No ratio) than lower order schemes like BPSK to achieve the same BER performance.
2) 16-QAM requires less energy than 16-PSK to achieve the same BER, since QAM signal points are distributed without being confined to a circle like PSK.
3) Simulated BER performance matches theoretical curves closely for Q
IRJET- Study of MIMO Precoding Techniques and their Application using Joi...IRJET Journal
This document discusses a study of MIMO precoding techniques and their application using joint spatial-division and multiplexing (JSDM) to address challenges in frequency-division duplex massive MIMO systems. It proposes a two-tier precoding approach with an outer precoder to mitigate inter-cluster interference based on statistical channel information and an inner precoder to spatially multiplex intra-cluster users. This approach reduces overhead and complexity compared to conventional techniques by exploiting channel correlations between users within clusters. The document also derives an iterative algorithm to track the outer precoder online and analyzes its tracking performance over time-varying channels.
Application of smart antenna interference suppression techniques in tdscdmamarwaeng
This document discusses the application of smart antenna interference suppression techniques in TD-SCDMA systems. It first provides background on TD-SCDMA and smart antenna technology. It then describes two adaptive beamforming algorithms - LMS and RLS - and simulates their performance at interference suppression in MATLAB. The simulation results show that both algorithms can effectively form a main beam towards the desired user and nulls towards interferers. RLS converges faster than LMS, though it has higher computational complexity. The study demonstrates that smart antenna techniques can improve signal quality in TD-SCDMA systems by suppressing interference.
This document proposes a multi-application multi-step mapping method for mapping multiple applications simultaneously onto a many-core Network-on-Chip (NoC). The method consists of two steps: 1) an application mapping step that finds a region on the NoC for each application using maximal empty rectangle techniques, and 2) a task mapping step that maps the tasks of each application within its region to minimize communication latency and energy consumption. The method aims to optimize the layout of applications and tasks to reduce network latency and energy usage for multi-application mapping on many-core NoCs.
Design and implementation a prototype system for fusion image by using SWT-PC...IJECEIAES
The technology of fusion image is dominance strongly over domain research for recent years, the techniques of fusion have various applications in real time used and proposed such as purpose of military and remote sensing etc., the fusion image is very efficient in processing of digital image. Single image produced from two images or more information of relevant combining process results from multi sensor fusion image. FPGA is the best implementation types of most technology enabling wide spread.This device works with modern versions for different critical characteristics same huge number of elements logic in order to permit complex algorithm implemented. In this paper,filters are designed and implemented in FPGA utilized for disease specified detection from images CT/MRI scanned where the samples are taken for human's brain with various medical images and the processing of fusion employed by using technique Stationary Wavelet Transform and Principal Component Analysis (SWT-PCA). Accuracy image output increases when implemented this technique and that was done by sampling down eliminating where effects blurring and artifacts doesn't influenced. The algorithm of SWT-PCA parameters quality measurements like NCC, MSE, PSNR, coefficients and Eigen values.The advantages significant of this system that provide real time, time rapid to market and portability beside the change parametric continuing in the DWT transform. The designed and simulation of module proposed system has been done by using MATLAB simulink and blocks generator system, Xilinx synthesized with synthesis tool (XST) and implemented in XilinxSpartan 6-SP605 device.
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.
Towards the Performance Analysis of IEEE 802.11 in Multi-hop Ad-Hoc Networksambitlick
This document proposes analytical models to analyze the performance of the IEEE 802.11 protocol under unsaturated traffic conditions in multi-hop wireless networks. It presents a two-dimensional Markov chain model to describe the behavior of IEEE 802.11 under different offered traffic loads, showing the effect of load on transmission probability. It also proposes a three-dimensional model to describe multi-hop 802.11 networks, modeling not only data sources but also relay stations forwarding traffic. The models are validated through ns-2 simulations with different network configurations for metrics like throughput, delay, queue length, and energy consumption.
Frequency domain behavior of S-parameters piecewise-linear fitting in a digit...Piero Belforte
This paper describes PWLFIT+, an extension to the frequency domain ofPWLFIT, a new paradigm in time-domain macromodel ing for linear multiportsystems, based on a piecewise-linea r (PWL) behavioral representation of the S-parameters step response.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This document compares the performance of three mobile ad hoc network (MANET) routing protocols: AODV, FSR, and IERP. It uses the QualNet network simulator to evaluate these protocols based on various metrics like throughput, average jitter, average end-to-end delay, and packet delivery ratio. The protocols are evaluated under different node speeds on a grid topology network with 90 nodes over an area of 1500x1500 meters. Simulation results show that AODV generally performs best in terms of throughput and packet delivery ratio across varying node speeds, while FSR performs worst for these metrics. IERP shows the worst performance for average end-to-end delay and average jitter as node speed increases.
DIGITAL WAVE SIMULATION OF LOSSY LINES FOR MULTI-GIGABIT APPLICATIONPiero Belforte
Frequency domain Vector Fitting (VF) is a well known technique to generate circuital models of a spatially discretized lossy transmission lines from theoretical formulation of losses. The sub-picosecond time steps required by multi-gigahertz bandwidths and short transmission lines included in the models, determine long Spice simulation times. A 100X speedup can be gained using the Digital Wave Simulator (DWS) instead of Spice. DWS processes the waves of a Digital Network built up connecting together scattering blocks (circuit elements, nodes and S-parameter multi-ports) coming from a Spice-like description. Being a DSP wave processor instead of a classical nodal equations solver, DWS is computationally very fast and numerically stable. Comparisons with commercial simulators like Microcap11 and CST Cable Studio show a good matching of results. A further 10-100X simulation speedup is obtained if Piecewise-Linear Fitting (PWLF) is used to describe the time-domain behaviors of Scattering Parameters. Single or multiple cell Behavioral Time Models (BTM) can be extracted by PWLF from TDR/TDT measurements and processed by DWS fast convolution algorithms. A setup de-embedding can be performed by pwl breakpoints optimization to fit actual measurements. A RG58 coaxial cable is analyzed and its VF-derived eye-diagrams are compared to PWLF measurement-derived results. At multi-gigabit rates significant differences, due to cable physical implementation effects, are observed. The modeling/simulation alternatives (VF/Spice, VF/DWS and PWLF/DWS) are compared together and the advantages of PWLF/DWS in term of simplicity, stability and speed are highlighted.
Design of magnetic dipole based 3D integration nano-circuits for future elect...VIT-AP University
Nano Magnetic Logic (NML) has been attracting application in optical computing, nanodevice formation, and low power. In this paper nanoscale architecture such as the decoder, multiplexer, and comparator are implemented on perpendicular-nano magnetic logic (pNML) technology. All these architectures with the superiority of minimum complexity and minimum delay are pointed. The proposed architectures have been designed using pNML in MagCAD tool, simulated with modelsim platform and correctness shown by simulation waveform. The correctness of these designs can be verified easily when Verilog code is generated from MagCAD tool. The performance of the proposed comparator towards default parameters shows the area of 2.4336 μm2 and critical path of 1.5E-7 sec. As a higher order, the realization of a 4-to-1 multiplexer in NML has also been included in this work.
This paper discusses constructing optimal frequency hopping sequences for use in TDMA-FDMA cellular systems operating in fading channels. It reviews conditions for frequency and time channels to fade independently based on coherence time and bandwidth. The paper presents an algebraic construction of frequency hopping sequences based on linear congruences that guarantees sufficient channel separation to achieve maximum frequency diversity. Examples applicable to the GSM system are provided.
A Broadband Wireless Access technology known as
Worldwide Interoperability for Microwave Access (WiMAX) is
based on IEEE 802.16 standards. It uses orthogonal frequency
division multiple accesses (OFDMA) as one of its multiple access
technique. Major design factors of OFDMA resource allocation are
scheduling and burst allocation. To calculate the appropriate
dimensions and location of each user’s data so as to construct the
bursts in the downlink subframe, is the responsibility of burst
allocation algorithm. Bursts are calculated in terms of number of
slots for each user. Burst Allocation Algorithm is used to overcome
the resource wastage in the form of unused and unallocated slots per
frame. It affects the Base station performance in mobile WiMAX
systems. In this Paper, HOCSA (Hybrid One Column Striping with
Non Increasing Area) algorithm is proposed to overcome frame
wastage. HOCSA is implemented by improving eOCSA algorithm
and is evaluated using MATLAB. HOCSA achieves significant
reduction of resource wastage per frame, leading to more
exploitation of the WiMAX frame.
Wideband Modeling of Twisted-Pair Cables for MIMO ApplicationsLantiq
Computer modeling and simulation approach to speed development of broadband networking technologies. http://bit.ly/1853xoY
More on our expertise: http://www.lantiq.com
This document summarizes a research paper on developing a reconfigurable hardware architecture for implementing maximum likelihood (ML) decoding algorithms in MIMO systems. It begins by introducing MIMO techniques for improving wireless communication throughput. It then describes various MIMO receiver algorithms and chooses ML for its best performance. The document outlines the ML decoding algorithm and presents a Simulink model. It discusses implementing the MIMO decoder as a modular, reconfigurable architecture on an FPGA and shows placement results on a Xilinx Virtex 4 chip. The work aims to provide flexible hardware for MIMO signal processing applications.
CONFIGURABLE TASK MAPPING FOR MULTIPLE OBJECTIVES IN MACRO-PROGRAMMING OF WIR...ijassn
Macro-programming is the new generation advanced method of using Wireless Sensor Network (WSNs), where application developers can extract data from sensor nodes through a high level abstraction of the system. Instead of developing the entire application, task graph representation of the WSN model presents simplified approach of data collection. However, mapping of tasks onto sensor nodes highlights several problems in energy consumption and routing delay. In this paper, we present an efficient hybrid approach of task mapping for WSN – Hybrid Genetic Algorithm, considering multiple objectives of optimization – energy consumption, routing delay and soft real time requirement. We also present a method to configure the algorithm as per user's need by changing the heuristics used for optimization. The trade-off analysis between energy consumption and delivery delay was performed and simulation results are presented. The algorithm is applicable during macro-programming enabling developers to choose a better mapping according to their application requirements.
This document discusses two schemes for implementing multirate transmission in fiber-optic code-division multiple access (CDMA) networks: the parallel scheme and the serial mapping scheme. The parallel scheme assigns each user multiple addresses based on their data rate and encodes bits in parallel. The serial mapping scheme encodes bits serially using optical orthogonal codes (OOCs) constructed from frequency hop codes. Analysis shows the parallel scheme can support error correction coding to increase network capacity, while the serial mapping performs well even without coding. Both schemes allow accommodating high numbers of multirate users without increasing optical processing complexity.
A New Approach for Solving Inverse Scattering Problems with Overset Grid Gene...TELKOMNIKA JOURNAL
This paper presents a new approach of Forward-Backward Time-Stepping (FBTS)
utilizing Finite-Difference Time-Domain (FDTD) method with Overset Grid Generation (OGG)
method to solve the inverse scattering problems for electromagnetic (EM) waves. The proposed
FDTD method is combined with OGG method to reduce the geometrically complex problem to a
simple set of grids. The grids can be modified easily without the need to regenerate the grid
system, thus, it provide an efficient approach to integrate with the FBTS technique. Here, the
characteristics of the EM waves are analyzed. For the research mentioned in this paper, the
‘measured’ signals are syntactic data generated by FDTD simulations. While the ‘simulated’
signals are the calculated data. The accuracy of the proposed approach is validated. Good
agreements are obtained between simulation data and measured data. The proposed approach
has the potential to provide useful quantitative information of the unknown object particularly for
shape reconstruction, object detection and others.
Macromodel of High Speed Interconnect using Vector Fitting Algorithmijsrd.com
At high frequency efficient macromodeling of high speed interconnects is all time challenging task. We have presented systematic methodologies to generate rational function approximations of high-speed interconnects using vector fitting technique for any type of termination conditions and construct efficient multiport model, which is easily and directly compatible with circuit simulators.
This document presents a new adaptive algorithm for an adaptive decision feedback equalizer (ADFE) that has lower computational complexity than existing algorithms. The proposed block-based normalized least mean square (BBNLMS) algorithm with set-membership filtering for the ADFE achieves similar bit error rate performance and convergence speed as conventional algorithms like set-membership normalized least mean square (SM-NLMS), but with significantly fewer computations. Simulation results show the new algorithm provides comparable equalization performance to SM-NLMS while realizing about a 70% reduction in computational operations, especially at high signal-to-noise ratios, making it suitable for high-speed decision feedback equalization applications.
TriBA(Triplet Based Architecture) is a Network on Chip processor(NoC) architecture which merges the
core philosophy of Object Oriented Design with the hardware design of multicore processors[1].We
present TriBASim in this paper, a NoC simulator specifically designed for TriBA.In TriBA ,nodes are
connected in recursive triplets .TriBA network topology performance analysis have been carried out from
different perspectives [2] and routing algorithms have been developed [3][4] but the architecture still lacks
a simulator that the researcher can use to run simple and fast behavioural analysis on the architecture
based on common parameters in the Network On Chip arena. TriBASim is introduced in this paper ,a
simulator for TriBA ,based on systemc[6] .TriBASim will lessen the burden on researchers on TriBA ,by
giving them something to just plug in desired parameters and have nodes and topology set up ready for
analysis.
Digital Wave Simulation of Quasi-Static Partial Element Equivalent Circuit Me...Piero Belforte
This is an extended version of the paper published on IEEE Transactions on EMC, October 2016. PEEC modeling is a well established technique for obtaining a circuit equivalent for an electromagnetic problem. The time domain solution of such models is usually performed using nodal voltages and branch currents, or sometimes charge and currents. The present paper describes a possible alternative approach which can be obtained expressing and solving the problem in the waves domain. The digital wave theory is used to find an equivalent representation of the PEEC circuit in the wave domain. Through a pertinent continuous to discrete time transformation, the constitutive relations for partial inductances, capacitances and resistances are translated in an explicit form. The combination of such equations with Kirchhoff laws allows to achieve a semi-explicit resolution scheme. Three different physical configurations are analyzed and their extracted Digital Wave PEEC models are simulated at growing sizes using the general-purpose Digital Wave Simulator (DWS). The results are compared to those obtained by using standard SPICE simulators in both linear and nonlinear cases. When the size of the model is manageable by SPICE, an excellent accuracy and a speed-up factor of up to three orders of magnitude are observed with much lower memory requirements. PEEC model sizes manageable by DWS are also an order of magnitude larger than SPICE. A comparative analysis of results including the effect of parameters like the simulation time step choice is also presented.
This document discusses a proposed low-cost method for distributing nodes in a hexagonal pattern for wireless sensor networks. The method uses multidimensional scaling to determine the distribution of sensor nodes across a geographic area and estimates the computational cost of the system. Simulation results show that using a hexagonal distribution provides 100% coverage of the area with low computational costs for over 100 nodes, and less range error compared to random or square distributions. The proposed hexagonal method aims to optimize network coverage for wireless sensor networks.
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 proposes a multi-application multi-step mapping method for mapping multiple applications simultaneously onto a many-core Network-on-Chip (NoC). The method consists of two steps: 1) an application mapping step that finds a region on the NoC for each application using maximal empty rectangle techniques, and 2) a task mapping step that maps the tasks of each application within its region to minimize communication latency and energy consumption. The method aims to optimize the layout of applications and tasks to reduce network latency and energy usage for multi-application mapping on many-core NoCs.
Design and implementation a prototype system for fusion image by using SWT-PC...IJECEIAES
The technology of fusion image is dominance strongly over domain research for recent years, the techniques of fusion have various applications in real time used and proposed such as purpose of military and remote sensing etc., the fusion image is very efficient in processing of digital image. Single image produced from two images or more information of relevant combining process results from multi sensor fusion image. FPGA is the best implementation types of most technology enabling wide spread.This device works with modern versions for different critical characteristics same huge number of elements logic in order to permit complex algorithm implemented. In this paper,filters are designed and implemented in FPGA utilized for disease specified detection from images CT/MRI scanned where the samples are taken for human's brain with various medical images and the processing of fusion employed by using technique Stationary Wavelet Transform and Principal Component Analysis (SWT-PCA). Accuracy image output increases when implemented this technique and that was done by sampling down eliminating where effects blurring and artifacts doesn't influenced. The algorithm of SWT-PCA parameters quality measurements like NCC, MSE, PSNR, coefficients and Eigen values.The advantages significant of this system that provide real time, time rapid to market and portability beside the change parametric continuing in the DWT transform. The designed and simulation of module proposed system has been done by using MATLAB simulink and blocks generator system, Xilinx synthesized with synthesis tool (XST) and implemented in XilinxSpartan 6-SP605 device.
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.
Towards the Performance Analysis of IEEE 802.11 in Multi-hop Ad-Hoc Networksambitlick
This document proposes analytical models to analyze the performance of the IEEE 802.11 protocol under unsaturated traffic conditions in multi-hop wireless networks. It presents a two-dimensional Markov chain model to describe the behavior of IEEE 802.11 under different offered traffic loads, showing the effect of load on transmission probability. It also proposes a three-dimensional model to describe multi-hop 802.11 networks, modeling not only data sources but also relay stations forwarding traffic. The models are validated through ns-2 simulations with different network configurations for metrics like throughput, delay, queue length, and energy consumption.
Frequency domain behavior of S-parameters piecewise-linear fitting in a digit...Piero Belforte
This paper describes PWLFIT+, an extension to the frequency domain ofPWLFIT, a new paradigm in time-domain macromodel ing for linear multiportsystems, based on a piecewise-linea r (PWL) behavioral representation of the S-parameters step response.
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
This document compares the performance of three mobile ad hoc network (MANET) routing protocols: AODV, FSR, and IERP. It uses the QualNet network simulator to evaluate these protocols based on various metrics like throughput, average jitter, average end-to-end delay, and packet delivery ratio. The protocols are evaluated under different node speeds on a grid topology network with 90 nodes over an area of 1500x1500 meters. Simulation results show that AODV generally performs best in terms of throughput and packet delivery ratio across varying node speeds, while FSR performs worst for these metrics. IERP shows the worst performance for average end-to-end delay and average jitter as node speed increases.
DIGITAL WAVE SIMULATION OF LOSSY LINES FOR MULTI-GIGABIT APPLICATIONPiero Belforte
Frequency domain Vector Fitting (VF) is a well known technique to generate circuital models of a spatially discretized lossy transmission lines from theoretical formulation of losses. The sub-picosecond time steps required by multi-gigahertz bandwidths and short transmission lines included in the models, determine long Spice simulation times. A 100X speedup can be gained using the Digital Wave Simulator (DWS) instead of Spice. DWS processes the waves of a Digital Network built up connecting together scattering blocks (circuit elements, nodes and S-parameter multi-ports) coming from a Spice-like description. Being a DSP wave processor instead of a classical nodal equations solver, DWS is computationally very fast and numerically stable. Comparisons with commercial simulators like Microcap11 and CST Cable Studio show a good matching of results. A further 10-100X simulation speedup is obtained if Piecewise-Linear Fitting (PWLF) is used to describe the time-domain behaviors of Scattering Parameters. Single or multiple cell Behavioral Time Models (BTM) can be extracted by PWLF from TDR/TDT measurements and processed by DWS fast convolution algorithms. A setup de-embedding can be performed by pwl breakpoints optimization to fit actual measurements. A RG58 coaxial cable is analyzed and its VF-derived eye-diagrams are compared to PWLF measurement-derived results. At multi-gigabit rates significant differences, due to cable physical implementation effects, are observed. The modeling/simulation alternatives (VF/Spice, VF/DWS and PWLF/DWS) are compared together and the advantages of PWLF/DWS in term of simplicity, stability and speed are highlighted.
Design of magnetic dipole based 3D integration nano-circuits for future elect...VIT-AP University
Nano Magnetic Logic (NML) has been attracting application in optical computing, nanodevice formation, and low power. In this paper nanoscale architecture such as the decoder, multiplexer, and comparator are implemented on perpendicular-nano magnetic logic (pNML) technology. All these architectures with the superiority of minimum complexity and minimum delay are pointed. The proposed architectures have been designed using pNML in MagCAD tool, simulated with modelsim platform and correctness shown by simulation waveform. The correctness of these designs can be verified easily when Verilog code is generated from MagCAD tool. The performance of the proposed comparator towards default parameters shows the area of 2.4336 μm2 and critical path of 1.5E-7 sec. As a higher order, the realization of a 4-to-1 multiplexer in NML has also been included in this work.
This paper discusses constructing optimal frequency hopping sequences for use in TDMA-FDMA cellular systems operating in fading channels. It reviews conditions for frequency and time channels to fade independently based on coherence time and bandwidth. The paper presents an algebraic construction of frequency hopping sequences based on linear congruences that guarantees sufficient channel separation to achieve maximum frequency diversity. Examples applicable to the GSM system are provided.
A Broadband Wireless Access technology known as
Worldwide Interoperability for Microwave Access (WiMAX) is
based on IEEE 802.16 standards. It uses orthogonal frequency
division multiple accesses (OFDMA) as one of its multiple access
technique. Major design factors of OFDMA resource allocation are
scheduling and burst allocation. To calculate the appropriate
dimensions and location of each user’s data so as to construct the
bursts in the downlink subframe, is the responsibility of burst
allocation algorithm. Bursts are calculated in terms of number of
slots for each user. Burst Allocation Algorithm is used to overcome
the resource wastage in the form of unused and unallocated slots per
frame. It affects the Base station performance in mobile WiMAX
systems. In this Paper, HOCSA (Hybrid One Column Striping with
Non Increasing Area) algorithm is proposed to overcome frame
wastage. HOCSA is implemented by improving eOCSA algorithm
and is evaluated using MATLAB. HOCSA achieves significant
reduction of resource wastage per frame, leading to more
exploitation of the WiMAX frame.
Wideband Modeling of Twisted-Pair Cables for MIMO ApplicationsLantiq
Computer modeling and simulation approach to speed development of broadband networking technologies. http://bit.ly/1853xoY
More on our expertise: http://www.lantiq.com
This document summarizes a research paper on developing a reconfigurable hardware architecture for implementing maximum likelihood (ML) decoding algorithms in MIMO systems. It begins by introducing MIMO techniques for improving wireless communication throughput. It then describes various MIMO receiver algorithms and chooses ML for its best performance. The document outlines the ML decoding algorithm and presents a Simulink model. It discusses implementing the MIMO decoder as a modular, reconfigurable architecture on an FPGA and shows placement results on a Xilinx Virtex 4 chip. The work aims to provide flexible hardware for MIMO signal processing applications.
CONFIGURABLE TASK MAPPING FOR MULTIPLE OBJECTIVES IN MACRO-PROGRAMMING OF WIR...ijassn
Macro-programming is the new generation advanced method of using Wireless Sensor Network (WSNs), where application developers can extract data from sensor nodes through a high level abstraction of the system. Instead of developing the entire application, task graph representation of the WSN model presents simplified approach of data collection. However, mapping of tasks onto sensor nodes highlights several problems in energy consumption and routing delay. In this paper, we present an efficient hybrid approach of task mapping for WSN – Hybrid Genetic Algorithm, considering multiple objectives of optimization – energy consumption, routing delay and soft real time requirement. We also present a method to configure the algorithm as per user's need by changing the heuristics used for optimization. The trade-off analysis between energy consumption and delivery delay was performed and simulation results are presented. The algorithm is applicable during macro-programming enabling developers to choose a better mapping according to their application requirements.
This document discusses two schemes for implementing multirate transmission in fiber-optic code-division multiple access (CDMA) networks: the parallel scheme and the serial mapping scheme. The parallel scheme assigns each user multiple addresses based on their data rate and encodes bits in parallel. The serial mapping scheme encodes bits serially using optical orthogonal codes (OOCs) constructed from frequency hop codes. Analysis shows the parallel scheme can support error correction coding to increase network capacity, while the serial mapping performs well even without coding. Both schemes allow accommodating high numbers of multirate users without increasing optical processing complexity.
A New Approach for Solving Inverse Scattering Problems with Overset Grid Gene...TELKOMNIKA JOURNAL
This paper presents a new approach of Forward-Backward Time-Stepping (FBTS)
utilizing Finite-Difference Time-Domain (FDTD) method with Overset Grid Generation (OGG)
method to solve the inverse scattering problems for electromagnetic (EM) waves. The proposed
FDTD method is combined with OGG method to reduce the geometrically complex problem to a
simple set of grids. The grids can be modified easily without the need to regenerate the grid
system, thus, it provide an efficient approach to integrate with the FBTS technique. Here, the
characteristics of the EM waves are analyzed. For the research mentioned in this paper, the
‘measured’ signals are syntactic data generated by FDTD simulations. While the ‘simulated’
signals are the calculated data. The accuracy of the proposed approach is validated. Good
agreements are obtained between simulation data and measured data. The proposed approach
has the potential to provide useful quantitative information of the unknown object particularly for
shape reconstruction, object detection and others.
Macromodel of High Speed Interconnect using Vector Fitting Algorithmijsrd.com
At high frequency efficient macromodeling of high speed interconnects is all time challenging task. We have presented systematic methodologies to generate rational function approximations of high-speed interconnects using vector fitting technique for any type of termination conditions and construct efficient multiport model, which is easily and directly compatible with circuit simulators.
This document presents a new adaptive algorithm for an adaptive decision feedback equalizer (ADFE) that has lower computational complexity than existing algorithms. The proposed block-based normalized least mean square (BBNLMS) algorithm with set-membership filtering for the ADFE achieves similar bit error rate performance and convergence speed as conventional algorithms like set-membership normalized least mean square (SM-NLMS), but with significantly fewer computations. Simulation results show the new algorithm provides comparable equalization performance to SM-NLMS while realizing about a 70% reduction in computational operations, especially at high signal-to-noise ratios, making it suitable for high-speed decision feedback equalization applications.
TriBA(Triplet Based Architecture) is a Network on Chip processor(NoC) architecture which merges the
core philosophy of Object Oriented Design with the hardware design of multicore processors[1].We
present TriBASim in this paper, a NoC simulator specifically designed for TriBA.In TriBA ,nodes are
connected in recursive triplets .TriBA network topology performance analysis have been carried out from
different perspectives [2] and routing algorithms have been developed [3][4] but the architecture still lacks
a simulator that the researcher can use to run simple and fast behavioural analysis on the architecture
based on common parameters in the Network On Chip arena. TriBASim is introduced in this paper ,a
simulator for TriBA ,based on systemc[6] .TriBASim will lessen the burden on researchers on TriBA ,by
giving them something to just plug in desired parameters and have nodes and topology set up ready for
analysis.
Digital Wave Simulation of Quasi-Static Partial Element Equivalent Circuit Me...Piero Belforte
This is an extended version of the paper published on IEEE Transactions on EMC, October 2016. PEEC modeling is a well established technique for obtaining a circuit equivalent for an electromagnetic problem. The time domain solution of such models is usually performed using nodal voltages and branch currents, or sometimes charge and currents. The present paper describes a possible alternative approach which can be obtained expressing and solving the problem in the waves domain. The digital wave theory is used to find an equivalent representation of the PEEC circuit in the wave domain. Through a pertinent continuous to discrete time transformation, the constitutive relations for partial inductances, capacitances and resistances are translated in an explicit form. The combination of such equations with Kirchhoff laws allows to achieve a semi-explicit resolution scheme. Three different physical configurations are analyzed and their extracted Digital Wave PEEC models are simulated at growing sizes using the general-purpose Digital Wave Simulator (DWS). The results are compared to those obtained by using standard SPICE simulators in both linear and nonlinear cases. When the size of the model is manageable by SPICE, an excellent accuracy and a speed-up factor of up to three orders of magnitude are observed with much lower memory requirements. PEEC model sizes manageable by DWS are also an order of magnitude larger than SPICE. A comparative analysis of results including the effect of parameters like the simulation time step choice is also presented.
This document discusses a proposed low-cost method for distributing nodes in a hexagonal pattern for wireless sensor networks. The method uses multidimensional scaling to determine the distribution of sensor nodes across a geographic area and estimates the computational cost of the system. Simulation results show that using a hexagonal distribution provides 100% coverage of the area with low computational costs for over 100 nodes, and less range error compared to random or square distributions. The proposed hexagonal method aims to optimize network coverage for wireless sensor networks.
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
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
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 summarizes a research paper on improving vehicle-to-roadside unit communication using WiMAX technology. The researchers implemented a VANET simulation scenario in Qualnet to test connectivity between vehicles and roadside units. They found that using WiMAX instead of DSRC reduced packet loss from 58% to 8% at 72 km/h and lowered latency times. The appropriate routing protocol for the WiMAX scenario was determined to be AODV, as it had lower latency than DSR. The simulation showed that WiMAX increased the network range tremendously from 1.8km to 50km compared to DSRC. The study aims to enhance safety and reduce traffic accidents by improving connectivity between vehicles and roadside infrastructure.
The document discusses static and fatigue analysis of a modified multi-leaf spring used in light commercial vehicle (LCV) suspension systems. Finite element analysis is performed on the modified 7-leaf steel spring model to analyze stress, deflection, and stiffness. Fatigue life of the modified spring is also predicted using fatigue analysis software. The results from the finite element and fatigue analyses are compared to analytical calculations to validate the model and predicted fatigue life of the modified leaf spring design.
This document summarizes a research paper that proposes using prosody (rhythm, stress, intonation) information from user utterances to help a spoken dialogue system determine the user's level of certainty. It describes annotating a travel dialogue corpus for levels of certainty. Acoustic prosody features are extracted from utterances and used to train a classifier, achieving better certainty classification than a non-prosodic model. The paper argues that determining certainty from prosody could help dialogue systems respond more appropriately based on the user's mental state.
This document discusses the detection of "smart worms", which are malicious software programs that can intelligently manipulate their scanning behavior to avoid detection. The authors propose a novel spectrum-based scheme to detect smart worms using power spectral density analysis of traffic volumes. Their scheme analyzes the spectral flatness measure of worm traffic compared to background traffic. Evaluation results demonstrate the scheme can effectively detect smart worm propagation and outperforms existing detection methods. The authors also show it can detect traditional worms.
This document presents a new approach to redesigning the basic operators used in parallel prefix adders when implementing them in FPGAs. Parallel prefix adders are commonly used for high-speed binary addition. They work by using generate and propagate signals to compute the carry inputs at each stage in parallel. Typically, two operators called "black" and "gray" are used to compute the generate and propagate signals. The authors propose redesigning these basic operators by using multiplexers instead of logic gates, to better match the structure of FPGA slices. They implement several parallel prefix adders, including Brent-Kung, Skalansky, and Kogge-Stone adders, using the original and redesigned operators on
This document describes a computer integrated network solution for power plants in Poland called Badel. The network would connect process levels with plant operator levels.
The process levels would consist of microprocessor-based cells for monitoring heat and power generating units. These cells would be connected via local area networks and communicate process variables to the plant operator level.
The plant operator level would include a power plant database, control processor, and operator consoles for monitoring the plant. The network is intended to help operators monitor and control large power plants by integrating data collection from process levels and centralizing control and monitoring at the plant operator level. Performance evaluation of this integrated network solution for a power plant is the focus of the paper.
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
Pemerintah Indonesia berencana mengembangkan industri halal untuk meningkatkan ekspor dan pariwisata. Beberapa langkah yang akan dilakukan antara lain mempromosikan produk halal ke pasar global, meningkatkan sertifikasi produk halal, serta melatih SDM agar mampu bersaing di industri halal.
Presentación para Universidad del Istmo en PamplonaEduardo Valencia
Este documento habla brevemente sobre las tecnologías emergentes de realidad aumentada, mundos virtuales y dispositivos móviles en las décadas de 1990 y 2000, así como sobre el lenguaje de programación V-LANG y preguntas relacionadas con la publicidad viral y viajar alrededor del mundo.
The zookeeper repeatedly told visitors not to feed various zoo animals like monkeys, lions, bears, elephants, giraffes, parrots and zebras. Then the zookeeper announced that it was lunchtime for the zoo animals.
Data detection method for uplink massive MIMO systems based on the long recu...IJECEIAES
This document presents a new data detection method for uplink massive MIMO systems based on the long recurrence enlarged conjugate gradient (LRE-CG) approach. The minimum mean square error (MMSE) approach is near-optimal for uplink large-scale MIMO but involves matrix inversion, which is computationally complex. The proposed LRE-CG method iteratively approximates the MMSE solution without direct matrix inversion, using an orthonormal basis in the Krylov subspace to both update solutions and prevent complex inversions. Simulation results show the LRE-CG-based approach significantly reduces complexity while achieving near-optimal MMSE performance with a small number of iterations.
The document is the International Journal of Electronics and Communication Engineering & Technology (IJECET) from January 2014. It discusses a hybrid optimization method for multi-user detection in SDMA-OFDM systems that combines genetic algorithms and particle swarm optimization. This approach aims to overcome limitations of existing detection methods. The hybrid method is shown to provide better performance than minimum mean square error and maximum likelihood detection, especially when the number of users is high relative to base station antennas. The document provides details on the proposed hybrid method and compares its performance to other approaches through simulation.
Interoperator Dynamic Spectrum Sharing (Analysis, Costs and Implications)CSCJournals
This paper addresses Dynamic Spectrum Sharing (DSS) between two wireless operators. The Universal Mobile Telecommunication System (UMTS) network is used as a case study. The proposed protocol is evaluated under the uniform and non-uniform traffic conditions. The underlying principles of the algorithm can be deployed in the UMTS extension Band (2500MHz-2690MHz) which is yet to be allocated or the re-farmed GSM spectrum (900MHz/1800MHz). The simulation results for the proposed protocol shows that significant spectrum sharing gains can be obtained. However such spectrum efficiency gain need to be carefully balanced with the complexity in terms of latency (delays) and additional overhead it brings to the network. The results show that significant spectrum sharing gain of 4.0 % and 2.0 % can be obtained under uniform and non-uniform traffic conditions
Integrating millimeter wave with hybrid precoding multiuser massive MIMO for ...TELKOMNIKA JOURNAL
Nowadays, there has been growing interest in the Massive MIMO as a result of improving throughput by leveraging spatial freedom and array gain. It is equipped with millimeter wave (mm Wave) bands to resolve the high path-loss. It is known from the literature that iterated algorithms are usually used to attain the hybrid precoders to accomplish a specific optimization objective. Thus, the complexity remains high because each iteration may include singular value decomposition, the matrix inversion, and so on that motivates us to split the hybrid precoding and combining problem into sub-problems. The proposed solution is a multi-user Massive MIMO hybrid beamforming based on a convex optimization problem that is applied and solved for estimating the digital precoding to eliminate inter-user interference while using codebooks to select analog beamformers. It is apparent in the majority of cases; the proposed beamforming performance is higher than only-analog beamforming, single-user (no interference), the ZF precoding, the MMSE precoding, and the Kalman precoding where the full digital solution is a considerable as the benchmark point with different scenarios due to the reduction of user interference. Thus, there is no consideration for complicated operations such as SVD or inversion matrices as well as no need for data estimation. Our proposed solution can serve a large number of users simultaneously due to more directive gain by using numerous antennas at BS. Based on its less complexity and keeping performance, our solution can be recommended.
An investigation-on-efficient-spreading-codes-for-transmitter-based-technique...Cemal Ardil
This document summarizes research on efficient spreading codes for transmitter-based techniques to mitigate interference in time division duplex code division multiple access (TDD/CDMA) downlink systems. It investigates bitwise and blockwise multiuser transmission schemes that transfer complexity to the transmitter. Different spreading codes are evaluated based on correlation properties to determine suitability for techniques like precoding, pre-rake, and rake diversity. Performance is measured by bit error rate with varying numbers of users to identify the most efficient codes for interference mitigation.
ADAPTIVE RANDOM SPATIAL BASED CHANNEL ESTIMATION (ARSCE) FOR MILLIMETER WAVE ...IJCNCJournal
Millimeter-wave and mMIMO communications are the most essential success systems for next-generation wireless sensor networks to have enormous amounts of accessible throughput and spectrum. Through installing huge antenna arrays at the base station and performing coherent transceiver processing, mMIMO is a potential technology for enhancing the bandwidth efficiency of wireless sensor networks. The use of mmWave frequencies for mMIMO systems solves the problem of high path-loss through offering greater antenna gains. In this work, we provide a design with a random spatial sample structure that incorporates a totally random step before the analogue is received. It contains a totally random step before the analogue received signals are sent into the digital component of the HBF receiver. Adaptive random spatial based channel estimation (ARSCE) is proposed for channel session measurement collection, and an analogue combiner with valves has been used to estimate the signals at each receiving antenna. The proposed optimization problem formulation attempts to discover the orientations and gains of wideband channel routes. In addition, our proposed model has compared to various state-of-art techniques while considering error minimization.
Adaptive Random Spatial based Channel Estimation (ARSCE) for Millimeter Wave ...IJCNCJournal
Millimeter-wave and mMIMO communications are the most essential success systems for next-generation wireless sensor networks to have enormous amounts of accessible throughput and spectrum. Through installing huge antenna arrays at the base station and performing coherent transceiver processing, mMIMO is a potential technology for enhancing the bandwidth efficiency of wireless sensor networks. The use of mmWave frequencies for mMIMO systems solves the problem of high path-loss through offering greater antenna gains. In this work, we provide a design with a random spatial sample structure that incorporates a totally random step before the analogue is received. It contains a totally random step before the analogue received signals are sent into the digital component of the HBF receiver. Adaptive random spatial based channel estimation (ARSCE) is proposed for channel session measurement collection, and an analogue combiner with valves has been used to estimate the signals at each receiving antenna. The proposed optimization problem formulation attempts to discover the orientations and gains of wideband channel routes. In addition, our proposed model has compared to various state-of-art techniques while considering error minimization.
Performance Analysis of BER and Throughput of Different MIMO Systems using Di...IRJET Journal
The document discusses performance analysis of different MIMO systems using various modulation techniques. It analyzes bit error rate (BER) and throughput of MIMO-OFDM downlink systems using QPSK, 16QAM and 64QAM modulation. MIMO-OFDM combines multiple-input multiple-output (MIMO) technology with orthogonal frequency-division multiplexing (OFDM) to improve data rates and reliability in wireless communications. The analysis found that higher order modulations like 16QAM and 64QAM achieve higher data rates but at the cost of increased BER, while lower order modulations like QPSK provide better BER performance. SNR and guard intervals in the OFDM signal were also found to improve system performance.
A New Bit Split and Interleaved Channel Coding for MIMO DecoderIJARBEST JOURNAL
Authors:-C. Amar Singh Feroz1, S. Karthikeyan2, K. Mala3
Abstract– In wireless communications, the use of multiple antennas at both the
transmitter and receiver is a key technology to enable high data transmission without
additional bandwidth or transmit power. MIMO schemes are widely used in many
wireless standards, allowing higher throughput using spatial multiplexing techniques.
Bit split mapping based on JDD is designed. Here ETI coding is used for encoding and
Viterbi is used for decoding. Experimental results for 16-QAM and 64 QAM with the
code rate of ½ and 1/3 codes are shown to verify the proposed approach and to elucidate
the design tradeoffs in terms the BER performance. This bit split mapping based JDD
algorithm can greatly improve BER performance with different system settings.
An Integrated Approach of ACM and CDMA in a Novel Multi User Spatial Modulati...ijtsrd
This document discusses a proposed novel multi-user spatial modulation scheme that integrates adaptive coding and modulation (ACM). It begins with background on spatial modulation techniques and their advantages over other MIMO techniques in reducing complexity while maintaining spectral efficiency. It then presents the system model for the proposed two-user multiple access spatial modulation system, which introduces a switching unit to dynamically select modulation orders for each transmit antenna based on channel conditions, as determined by a receiver with an adaptive unit. This adaptive approach aims to improve performance by optimizing modulation levels according to channel state information feedback from the receiver to the transmitters.
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.
MIMO System Performance Evaluation for High Data Rate Wireless Networks usin...IJMER
Space–time block coding is used for data communication in fading channels by multiple
transmit antennas. Message data is encoded by applying a space–time block code and after the encoding
the data is break into ‘n’ streams of simultaneously transmitted strings through n transmit antennas. The
received signal at the receiver end is the superposition of the n transmitted signals distorted due to noise
.For data recovery maximum likelihood decoding scheme is applied through decoupling of the signals
transmitted from different antennas instead of joint detection. The maximum likelihood decoding scheme
applies the orthogonal structure of the space–time block code (OSTBC) and gives a maximum-likelihood
decoding algorithm based on linear processing at the receiver. In this paper orthogonal space–time
block codes based model is developed using Matlab/Simulink to get the maximum diversity order for a
given number of transmit and receive antennas subject with a simple decoding algorithm.
The simulink block of orthogonal space coding block with space–time block codes is applied with and
without gray coding. The OSTBC codes gives the maximum possible transmission rate for any number of
transmit antennas using any arbitrary real constellation such of M-PSK array. For different complex
constellation of M- PSK space–time block codes are applied that achieve 1/2 and 3/4 of the maximum
possible transmission rate for MIMO transmit antennas using different complex constellations.
IRJET- Hybrid Beamforming Based mmWave for Future Generation CommunicationIRJET Journal
This document summarizes research on hybrid beamforming for millimeter wave (mmWave) communication systems. Hybrid beamforming combines analog and digital beamforming to address issues with using large antenna arrays for mmWave massive MIMO. It reduces hardware costs and complexity compared to all-digital approaches by using fewer radio frequency chains. The document discusses how hybrid beamforming exploits the sparse nature of mmWave channels to focus antenna gains on key propagation paths. It also reviews codebook-based and spatially sparse precoding techniques for hybrid beamforming mmWave systems. Overall, the document outlines how hybrid beamforming is a practical solution to implement large-scale antenna systems for 5G networks operating in the mmWave spectrum.
International Journal of Computer Networks & Communications (IJCNC)IJCNCJournal
Beamforming for millimetre-wave (mmWave) frequencies has been studied for many years. It is considered as an important enabling technology for communications in these high-frequency ranges and it received a lot of attention in the research community. The special characteristics of the mmWave band made the beamforming problem a challenging one because it depends on many environmental and operational factors. These challenges made any model-based architecture fit only special applications, working scenarios, and specific environment geometry. All these reasons increased the need for more general machine learning based beamforming systems that can work in different environments and conditions. This increased the need for an extended adjustable dataset that can serve as a tool for any machine learning technique to build an efficient beamforming architecture. Deep MIMO dataset has been used in many architectures and designs and has proved its benefits and flexibility to fit in many cases. In this paper, we study the extension of collaborative beamforming that includes many cooperating base stations by studying the impact of User Equipment (UE) speed ranges on the beamforming performance, optimizing the parameters of the neural network architecture of the beamforming design, and suggesting the optimal design that gives the best performance for as a small dataset as possible. Suggested architecture can achieve the same performance achieved before with up to 33% reduction in the dataset size used to train the system which provides a huge reduction in the data collection and processing time.
A Review on Transmit Antenna Selection for Massive MIMO SystemsIRJET Journal
This document discusses transmit antenna selection algorithms for massive MIMO systems. It first reviews previous approaches that focused on maximizing the determinant of the channel matrix. It then proposes a new low-complexity algorithm called RAISE (Real-time Antenna-by-antenna Iterative Swapping Enhancement) that finds a near-optimal solution using a maximum-volume submatrix method instead of directly solving capacity maximization. Analysis shows RAISE converges fast while significantly reducing computational complexity and memory requirements compared to conventional algorithms, making it suitable for real-time implementation in massive MIMO. Simulation results demonstrate it achieves near-optimal capacity performance with lower complexity.
Power saving and optimal hybrid precoding in millimeter wave massive MIMO sys...TELKOMNIKA JOURNAL
The proliferation of wireless services emerging from use cases offifth-generation(5G) technology is posing many challenges on cellular communicationinfrastructure. They demand to connect a massive number of devices withenhanced data rates. The massive multiple-input multiple-output (MIMO)technology at millimeter-wave (mmWave) in combination with hybrid precodingemerges as a concrete tool to address the requirements of 5G networkdevelopments. But Massive MIMO systems consume significant power fornetwork operations. Hence the prior role is to improve the energy efficiency byreducing the power consumption. This paper presents the power optimizationmodels for massive MIMO systems considering perfect channel state information(CSI) and imperfect CSI. Further, this work proposes an optimal hybrid precodingsolution named extended simultaneous orthogonal matchingpursuit (ESOMP).Simulation results reveal that a constant sum-rate can be achieved in massiveMIMO systems while significantly reducing the power consumption. Theproposed extended SOMPhybrid precoder performsclose to the conventionaldigital beamforming method. Further, modulation schemes compatible withmassive MIMO systems are outlined and their bit error rate (BER) performance isinvestigated
RS Codes for Downlink LTE System over LTE-MIMO ChannelTELKOMNIKA JOURNAL
This document summarizes a study that used Reed-Solomon codes with a downlink Long Term Evolution (LTE) system over an LTE Multiple-Input Multiple-Output (MIMO) channel to improve performance. Reed-Solomon codes were chosen because they have low decoding complexity compared to convolutional and turbo codes. Simulation results showed that using Reed-Solomon codes decreased the bit error rate more than convolutional or turbo codes. Additionally, increasing the number of antennas in the LTE-MIMO channel provided further improvements to downlink LTE system performance. BPSK modulation provided better performance gains compared to QPSK when used with Reed-Solomon codes over the LTE-MIMO channel.
Scedasticity descriptor of terrestrial wireless communications channels for m...IJECEIAES
Fifth-generation (5G) wireless systems increased the bandwidth, improved the speed, and shortened the latency of communications systems. Various channel models are developed to study 5G. These channel models reproduce the stochastic properties of multiple-input multiple-output (MIMO) antennas by generating wireless multipath components (MPCs). The MPCs with similar properties in delay, angles of departure, and angles of arrival form clusters. The multipaths and multipath clusters serve as datasets to understand the properties of 5G. These datasets generated by the Cooperation in Science and Technology 2100 (COST 2100), International Mobile Telecommunications-2020 (IMT-2020), Quasi Deterministic Radio Channel Generator (QuaDRiGa), and Wireless World Initiative New Radio II (WINNER II) channel models are tested for their homoscedasticity based on Johansen's procedure. Results show that the COST 2100, QuaDRiGa, and WINNER II datasets are heteroscedastic, while the IMT-2020 dataset is homoscedastic.
Linear Transmit-Receive Strategies for Multi-User MIMO Wireless CommunicationIRJET Journal
This document discusses linear transmit-receive strategies for multi-user MIMO wireless communication. It begins with an abstract that introduces MIMO technology which uses multiple antennas at the transmitter and receiver to overcome signal fading and improve data throughput. The document then provides more details on MIMO concepts including that it uses multiple spatial channels to increase capacity. It also discusses how MIMO can exploit fading that is typically undesirable to achieve high capacities. Finally, it examines linear precoding techniques as a spatial division multiple access strategy for multi-user MIMO systems and quantifying the rate and power bounds of such techniques.
The document discusses investigating packet transmission strategies in a MIMO equipped mobile ad hoc network using space-time coding. It proposes a new scheduling algorithm that improves packet transmission rate and energy performance. The system is modeled in OPNET using 40 randomly distributed nodes. Simulation results show the new algorithm enhances transmission efficiency compared to other methods by controlling node firing and scheduling packet transmissions based on network conditions and traffic demands.
International Journal of Engineering Inventions (IJEI)
Jc2415921599
1. P.G.C. Vikram, N.Gopi Chand/ International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue4, July-August 2012, pp.1592-1599
Evaluation Of A High Performance Qr Decomposition-Based
Matrix Inversion Technique For Embedded Mimo Receivers
P.G.C. VIKRAM N.GOPI CHAND
M.Tech Student Scholar, DECS, M.Tech, Asst Professor
Dept of Electronics and Communication Dept of Electronics and Communication
Engineering, Engineering,
Nalanda Institute of Engineering and technology, Nalanda Institute of Engineering and technology,
Sattenapalli (M); Guntur (Dt); A.P, India Sattenapalli (M); Guntur (Dt); A.P, India
Abstract
Matrix inversion is an essential communication systems. For example MIMO-
computation for various algorithms which are OFDM systems use matrix inversion in equalization
employed in multi antenna wireless algorithms to remove the effect of the channel on the
communication systems. FPGAs are ideal signal [1], minimum mean square error algorithms for
platforms for wireless communication; however, pre-coding in spatial multiplexing [2] and detection-
the need for vast amounts of customization estimation algorithms in space-time coding [3].
throughout the design process of a matrix These systems often use a small number of antennas
inversion core can overwhelm the designer. (2 to 8) which results in small matrices to be inverted
Decomposition methods provide the analytic and/or decomposed. For example the 802.11n
simplicity and computational convenience standard specifies a maximum of 4 antennas on the
necessary for computationally intensive matrix transmit/receive sides and the 802.16 standard
inversion. Real-time matrix inversion is a key specifies a maximum of 16 antennas at a base station
enabling technology in multiple-input multiple- and 2 antennas at a remote station. Matrix inversion
output (MIMO) communications systems, such as is a computationally intensive calculation.
802.11n. To date, however, no matrix inversion Decomposition methods provide a means to simplify
implementation has been devised which supports this computation. There are different decomposition
real-time operation for these standards. In this methods, such as QR, LU and Cholesky, that solve
paper, we overcome this barrier by presenting a matrix inversion. The selection of the decomposition
novel matrix inversion algorithm which is ideally method depends on the characteristics of the given
suited to high performance floating-point matrix. For non-square matrices or when simple
implementation. We show how the resulting inversion to recover the data performs poorly, the
architecture offers fundamentally higher QR decomposition is used to generate an equivalent
performance than currently published matrix upper triangular system, allowing for detection using
inversion approaches and we use it to create the the sphere decomposition or M-algorithm. For
first reported architecture capable of supporting simpler detection via inversion of square channel
real-time 802.11n operation. Specifically, we matrices, the LU and Cholesky decompositions are
present a matrix inversion approach based on compatible with positive definite and nonsingular
modified squared Givens rotations (MSGR). This diagonally dominant square matrices,
is a new QR decomposition algorithm which respectively[4].
overcomes critical limitations in other QR
algorithms that prohibits their application to FPGAs are an ideal platform for wireless
MIMO systems. In addition, we present a novel communication due to their high processing power,
modification that further reduces the complexity flexibility and non recurring engineering (NRE) cost.
of MSGR by almost 20%. This enables real-time However, FPGAs require vast amounts of
implementation with negligible reduction in the customization throughout the design process and few
accuracy of the inversion operation, or the BER of tools exist which can aid the designer with the many
a MIMO receiver based on this. system, architectural and logic design choices.
Designing a high level tool for fast prototyping
Keywords: BLAST, matrix inversion, multiple- matrix inversion architectures is crucial. Multi Input
input multiple- – Multi Output (MIMO) technology, such as BLAST
output (MIMO) , QR decomposition. [1]–[3] for WiFi or WiMAX offers the potential to
exploit spatial diversity in a communications channel
I. INTRODUCTION to increase its bandwidth without sacrificing larger
Matrix inversion is a common function portions of the radio spectrum. The general form of a
found in many algorithms used in wireless MIMO system composed of transmit and receive
1592 | P a g e
2. P.G.C. Vikram, N.Gopi Chand/ International Journal of Engineering Research and
Applications (IJERA) ISSN: 2248-9622 www.ijera.com
Vol. 2, Issue4, July-August 2012, pp.1592-1599
antennas is outlined in Figure. 1. Implementation of as fundamental as MMSE specifically to avoid
these systems involves satisfying the real-time explicit matrix inversion and clearly complicates the
performance requirements of the application (in terms design process in a way which is not required for less
of metrics such as throughput, latency, etc.), in a complex matrix operations such as addition or
manner which efficiently exploits the embedded multiplication. It also does not solve the long term
device(s) to implement such systems. problem, since algorithms such as the MMSE in [8]
exhibit the same O( ) complexity matrix inversion
algorithms [4]–[7]. As a result, as MIMO systems
grow larger to incorporate more antennas, both
solutions will tend to the same complexity. However,
given that the matrix inversion approaches in [4]–[7]
are all either throughput or latency deficient by a
factor of at least 2, there appear to be substantial
Figure 1: MIMO system Overview issues to be overcome before real-time matrix
inversion in systems such as 802.11n is feasible.
A key feature of MIMO receivers is their
reliance on matrix computations such as addition, Matrix inversion techniques are, generally,
multiplication and inversion— for instance, to enable either iterative or direct [9]. Iterative methods, such
operations such as minimum mean square error as the Jacobi or Gauss-Seidel methods, start with an
(MMSE) equalization during channel detection [3]. In estimate of the solution and iteratively update the
particular, complex matrix inversion has proven so estimate based on calculation of the error in the
difficult to implement that, to the best of the authors’ previous estimate, until a sufficiently accurate
knowledge, there are no reported implementations solution is derived. The sequential nature of this
capable of sustaining the 14.4 MInversions/s process can limit the amount of available parallelism
(MInv/s) and 4 latency required for modern IEEE and make high throughput implementation
802.11n MIMO systems [4]–[7]. As a result, to problematic [9]. On the other hand, direct methods
implement algorithms such as MMSE designers such as Gaussian elimination (GE), Cholesky
currently have to develop custom algorithms which decomposition (CD), and QRD typically compute the
avoid explicit matrix inversion [8]. This severely solution in a known, finite number of operations and
complicates the implementation process. This paper exhibit plentiful data and task-level parallelism.The
presents a new matrix inversion approach which complexity of a number of direct matrix inversion
overcomes this real-time performance barrier. We algorithms in MIMO communications systems
develop a general purpose complex-valued matrix composed of antennas, as well as an absolute
inversion algorithm and study its application to and complexity measure for .
integration in MIMO receiver algorithms and
embedded architectures. Specifically, we make three All these approaches exhibit similar
main contributions. complexity scaling: O( ) additions and
multiplications and O( ) divisions. Whilst
We derive a new QR decomposition (QRD)- relatively low complexity when compared to the
based algorithm known as modified squared Givens’ others, CD suffers from the drawback of requiring
rotations (MSGR), which overcomes key limitations symmetric matrices, a condition not guaranteed to
with other QRD-based approaches which hinder their occur in MIMO systems, limiting its applicability.
adoption in MIMO receiver architectures. We show Despite their relatively high complexity as compared
how the complexity of MSGR-based matrix inversion with CD, QRD approaches are an attractive
may be further reduced by almost 20% by removing a alternative not only because of their ability to
scale factor term, with little effect on its numerical overcome the symmetric restriction, but also because
stability, or the perceived BER of a MIMO receiver of their innate numerical stability [10]. Furthermore,
in which it is integrated. the plentiful data and task level parallelism available
in these algorithms has previously been
comprehensively exploited in a range of algorithms
II. BACKGROUND and architectures for recursive least squares (RLS) in
The need to detect 52 data subcarriers within adaptive beam forming and RADAR.
both the OFDM symbol and short inter frame spacing
periods of 802.11n places extreme real-time As regards QRD algorithms, Givens’
constraints on embedded signal processing rotations [14] QRD algorithms are more easily
architecture for these systems. For instance, [8] parallelized than Householder Transformations [15],
shows that there is no current matrix inversion but the methods for implementing Givens’ rotations,
implementation capable of sustaining the 14.4 i.e., conventional Givens’ rotations (CGR) [14],
MInvs/s with 4 latency for MMSE in 802. 11n. squared Givens’ rotations (SGR) [16], and CORDIC
This necessitates complicated redesign of algorithms [17] all place different constraints on
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Vol. 2, Issue4, July-August 2012, pp.1592-1599
implementations. The authors in [18] show that fixed- A is the inverse of the QR product and since Q is
point CORDIC-based QR algorithms are more unitary, is simply its Hermitian transpose .
accurate for linear MMSE detection of practical Given this, is given by (2). After QRD, inversion
MIMO-OFDM channels than SGR employing is much simpler because the inversion of the upper
conventional arithmetic. However this comes at an triangular matrix R can be derived using back
excessively high area cost due to the use of CORDIC substitution, as in
operators; indeed [8] and [19] report 3.5:1 and 3:1 = (Q =
area efficiency advantages when employing (2)
conventional mathematical operators as opposed to
CORDIC; [19] also describes a 25:1 sample rate
advantage associated with employing conventional
arithmetic and demonstrates that floating-point
arithmetic can be employed to overcome the (3)
precision issues outlined in [18] at no area cost. These Using SGR, the matrix A is decomposed as given in
factors seem to favour SGR-based implementation (4)–(8), where is in general not a unitary matrix,
over CORDIC. Whilst CGR does not fundamentally and U is an upper triangular matrix
require CORDIC for implementation, it does require
widespread use of costly square-root operations, and
is generally more computationally demanding than
SGR As such, the ability of SGR to avoid the use of
CORDIC and square-root operations, reduce overall
complexity and exploit floating-point arithmetic at no
area cost promises an appealing blend of numerical The inverse of the matrix A is then given by
stability and computational complexity. There are, (9). As U is an upper triangular matrix, its inverse can
however, a number of critical deficiencies which be found by back substitution, as in (3). In addition,
restrict its adoption in MIMO systems[10]. since (10) holds, inversion of this component is
simply a Hermitian transpose operation.
1) As described in Section III-B, SGR produces
erroneous results when zeros occur on the diagonal
elements of either the input matrix or the partially
decomposed matrices generated during the
triangularization.
2) Complex-valued SGR is highly computationally
To illustrate how MSGR extends SGR for
demanding and there are no reported variants which
complex-valued data, we use an example. Consider a
exhibit
3× 4 matrix of complex
significantly lower complexity whilst maintaining
values as in (11). MSGR generates an upper
accuracy.
triangular matrix, eliminating , and in a three-
3) There is no currently reported implementation of
stage approach
SGR based matrix inversion which can meet the high
real-time performance demands of modern MIMO
receivers. In this paper, we resolve these issues in a
new SGR approach, known as MSGR. Section III
derives MSGR specifically to overcome the issues in
1), before Section IV describes how the complexity
of this algorithm may be reduced by a further 20% Stage 1: Rotate rows r and a to eliminate element a1
with little reduction in accuracy, addressing 2). (i.e., update a1 to 1 such that 1 =0). To achieve this,
the MSGR updating quations can be written as (12)–
III. MODIFIED SGR FOR COMPLEX (14), where is the updated value of r
MATRIX INVERSION
A. Modified Squared Givens Rotations
Inversion of a matrix A can be performed by
firstly decomposing this into an upper triangular
form, which can be more easily inverted. QRD is one
such approach to perform this triangularization by From (13), (15) follows and therefore
decomposing A into two resulting matrices Q and R,
such that
A= QR
(1) Introducing , defined by (17), then combining (16)–
Q is a unitary matrix and R is an upper triangular (18) allows the update process for to be expressed as
matrix. From (1) it can be implied that the inverse of
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Vol. 2, Issue4, July-August 2012, pp.1592-1599
The final phase of translating the last row to
U -space is necessary in order to make the diagonal
element in this row a real value. The MSGR method
for the general case is described using (31)–(33)
where is the th column being processed.
Similarly, introducing as defined by (20), where is a
scale factor, then (14) can be written as [16]
These three stages define the sequence of
Effectively, and have been translated to U and V - operations of MSGR. There are, however, a number
space, respectively. Further, if (22) holds, then the of specific conditions under which SGR cannot
MSGR updating operate properly and produces erroneous results; this
equations from (12)–(14) can be rearranged as situation is maintained in MSGR. The nature of these
cases and a resolution to the resulting operational
issues is presented in Section III-B.
B. Processing Zero Values Incurred on the Matrix
Diagonal
To this point, it has been assumed that .
Stage 2: Rotate and TO ELIMINATE . Since is in - However, zeros can arise either in the input matrix or
space [given by (17)], row must now be translated to during phases of rotations, as illustrated in Figure 3.
-space for rotation according to Rotating two rows which have pairs of adjacent
equal-valued elements on the diagonal will result in
zeros on the first element (as desired) but also the
Equation (27) defines , where is real as undesirable occurrence of zeros in the diagonal
indicated by (15). Accordingly, updating of row b can position of the lower rotated row. During the next
be written as (28) phase of rotations, (i.e., rotations to zero the lower
(where indicates the second update of r) diagonal elements in the next column) the first
element of the -space is zero, leading to incorrect
operation of (31)–(33).
Stage 3: Rotate and to eliminate . To carry out
these rotations, must be translated from V-space to U-
space and must be translated to V-space, as
described in
Therefore, if we let the updated w= , then Figure 3: Diagonal zero element arisal.
the updated value of V= . This implies that the
updated scale factor must be used to translate in Due to this, an operational caveat must be
order to use as the new V-space vector for further applied before further rotations can be carried out. In
processing. The MSGR sequence of operations is [16], Dohler proposed a solution for dealing with u k =
illustrated in Figure. 2. 0, as given in
Despite this, the condition of both has not u k
= vk = 0 previously been considered, and the
solutions proposed in (34) prohibit further processing
based on these updated values. For example,
translation of a row from V-space to U -space (such
as that described in (29)) is not possible using
Figure 2: MSGR operation sequence. Dohler’s suggested updated scale factor =0 . To
overcome this problem, a novel solution uk = 0 for
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Vol. 2, Issue4, July-August 2012, pp.1592-1599
uk 0 , which permits subsequent processing, as well which depends on whether the cell processes diagonal
as a solution for uk = vk = 0, which has not been or off-diagonal elements—diagonal elements of the
previously considered, is given in input matrix are tagged with a flag (e.g. , ) as
shown in Figure 4. Furthermore, the zero-value
operational caveat described in Section III-B (i.e., uk
=0 ) is evident in these cells. Similarly, the IAM array
comprises boundary cells and internal cells which
This caveat fully defines MSGR-based carry out both the inversion of U by back-substitution
-1
matrix triangularization and has resolved the and subsequent multiplication by (QA . These
outstanding barriers to employing SGR for complex- finalize the MSGR-based matrix inversion algorithm.
valued matrix inversion. It remains to convert the
triangularized matrix to the inverse, which requires a Whilst our primary motivating application
suitable back-substitution operation. This back- for developing this new matrix inversion approach is
substitution process is outlined in Section III-C. MIMO systems, it is evident from the algorithm
description that MSGR-based matrix inversion can be
C. MSGR-Based Matrix Inversion used for inversion of complex matrices in any
Recalling (4) and (9), MSGR decomposes application. Since it is derived from SGR, MSGR
the input matrix as A= QA , which may be benefits from SGR’s inherent numerical stability. To
inverted as A-1= U-1(QA -1
. Inversion of the maximise the performance of embedded
upper triangular matrix can be computed using back- implementations of this algorithm, this complexity
substitution on the result of the MSGR operation, as should be reduced so far as is possible without
in (36) where G= U-1 significantly reducing the accuracy of the result. In
Section IV we describe a technique to achieve this
and analyze the effect of this simplification on the
accuracy of MSGR-based matrix inversion with
respect to a number of other standard approaches and
Given this back-substitution operation, on the performance of a state-of-the-art MIMO
according to (9), MSGR-based matrix inversion may receiver system.
be split into three sub-operations: decomposition of
the input matrix A into the upper triangular matrix U,
IV. REDUCED COMPLEXITY MSGR-
formation of U-1from U via back-substitution, and
finally multiplication by (QA -1
to form the
BASED MATRIXINVERSION FOR
-1
product U (QA -1
. We can use this to formulate BLAST MIMO
an operational model of MSGR-based matrix A. Reduced Complexity MSGR-Based Matrix
inversion to complement the mathematical model Inversion:
described thus far. In this section, we propose to remove the
-1
If we reformulate (9) as U= (QA A, scale factor and its associated computations (as
-1 described in Section III-C) from the MSGR cells to
then (QA can be considered to be the factor by
which A is multiplied to produce U, an operation reduce the complexity of MSGR-based matrix
which is achieved in the MSGR algorithm using inversion. Using MSGR without the -factor, the
rotations. Therefore, this factor can be isolated by matrix A is decomposed as in
multiplying by the identity matrix I, which is
equivalent to rotating I in the same manner as A.
Therefore, processing immediately after produces the
output (QA -1
. These two factors (U and (37)
-1
(QA ) are produced by an MSGR array.
is not normally an unitary matrix. Since
The formation of U-1 from U via back-
multiplication of the matrix rows by the scale factor
substitution, and subsequent multiplication by
-1 ω in (20) and (31) does not affect the matrix
(QA is then performed by an Invert and
properties, then the decomposition of using (37)
Multiply (IAM) Array. Dependence graphs of the
compared to standard MSGR (4), does not influence
MSGR and IAM arrays and the dataflow. The MSGR
the properties of U and Uw i.e., they are both
array produces an upper triangular matrix U given an
invertible upper triangular matrices. Therefore, for
input matrix A. It is also used to produce the
-1 MSGR without the ω factor, Uw is an invertible
component (QA given an input identity matrix .
upper triangular matrix and the inversion of A can be
It consists of two classes of operational unit:
given as in
boundary cells which translate the input data vectors
to U-space and internal cells for calculation of
rotation angles and subsequent rotation of the input
data. Note the bi-modal operation of these cells,
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Vol. 2, Issue4, July-August 2012, pp.1592-1599
(38)
Once all ω -related computations have been
removed, the MSGR array now produces an upper
triangular matrix Uw given an input matrix A It
also produces the component given an input
identity matrix . As Uw is an upper triangular matrix,
its inversion can be found by back-substitution. This
inversion and multiplication by is carried out
in the IAM array, as for the MSGR algorithm with -
factor included. It compares the number of operations
required for MSGR-based inversion of a 4 x 4 matrix
(b)
when the –factor has been included and excluded. As
Figure 4. ω-less MSGR-based matrix inversion
this shows, removing the ω factor has the significant
accuracy comparison. (a)Floating-point matrix
effect of reducing the number of multiplications and
inversion error. (b) Fixed-point matrix inversion
divisions by 19% and 18%, respectively. This
error.
represents a considerable performance advantage for
real-time implementation, in particular the reduction
To help gauge the accuracy of these results,
in the number of complex division operations, since
the errors encountered by alternative schemes are also
these are relatively expensive on implementation.
included. For floating-point data, we compare with
However, whilst the complexity reduction offered by
the results of complex matrix inversion as
removing the ω factor is clearly attractive, it is only
implemented using the LAPACK linear algebra
advantageous if it does not significantly reduce the
package (in this case implemented in the NAG
accuracy of the resulting inverted matrices, or the
Matlab toolkit)in Figure 4(a), while Figure 4(b)
accuracy of any MIMO receiver algorithm built upon
compares the accuracy of fixed-point MSGR with
MSGR-based matrix inversion. These two factors are
CORDIC-based matrix inversion. The results are
analyzed in Section IV-B and -C, respectively
shown in order of ascending error in Figure 4, for
easier interpretation. Figure 4(a) shows that the errors
B. Reduced Precision MSGR Accuracy Analysis: encountered in MSGR- based matrix inversion are,
The effect of removing the -factor on the more or less, the same as those encountered using
accuracy of the resulting inverted matrix is described LAPACK, and also show the expected increase in
in the graphs of Figure. 4. These two graphs measure absolute error when single precision data is used.
the deviation of the product of the original matrix and Figure 4(b) shows a similar relationship between
its inverse from the matrix (y axis) for each of 200 4 fixed-point MSGR and CORDIC, for various word
x4 MIMO rich scattering Rayleigh-fading channel size data. The dramatically larger errors encountered
matrices, which are enumerated on the axis. for a small number of matrices [represented by the
spikes at the end of the distributions in Figure4(b)]
are due to the occurrence of divide by zero
operations, and occur consistently in both MSGR and
CORDIC-based algorithms. However, the major
trend to note from Figure 4 is that reduced
complexity MSGR-based matrix inversion, without
the factor, has minimal impact on the accuracy of the
final solution, and provides solutions as accurate as
the comparable techniques.
C. MSGR-Based Matrix Inversion in BLAST
MIMO Receivers:
Real-time matrix inversion is vital in MIMO
(a) systems, for operations such as MMSE-based channel
detection, as described by (39). Here we study the
effect of removing the -factor on the BER of an
MMSE-based BLAST receiver system, specifically a
Turbo-BLAST (T-BLAST) scheme [3], [12]
(39)
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Vol. 2, Issue4, July-August 2012, pp.1592-1599
Here r is the received signal, H is the no appropriate solution to this problem for state-of
channel matrix and x is the estimate of the the- art MIMO systems, such as those in 802.11n
transmitted signal. To illustrate the effect of removing systems, with the large disparities between required
the -factor, Figure 5 shows the BER performance of a and actual performance indicating the need for a
4 x 4 T-BLAST receiver on a variable signal-to- thorough review of both algorithms and architectures
noise-ratio (SNR) rich scattering Rayleigh-fading employed. The work presented in this paper has
channel, under a variety of word size constraints with solved this problem. We have derived Modified
w either included or excluded. There are a number of Squared Givens’ rotations (MSGR), an algorithm for
trends evident in Figure 5. The close proximity of the QR-based matrix triangularization and inversion
curves for the variants including and excluding the ω which overcomes deficiencies in the standard SGR
factor in Figure 5 (which in the single precision, 20 algorithms. This provides a complex-valued matrix
bit floating-point and 32 bit fixed-point cases make inversion method which not only overcomes key
the curves indistinguishable) is that there is little factors for integration in MIMO systems, but also
degradation in the performance of the T-BLAST enables a suitable mechanism for complex matrix
receiver whether the ω factor is included or excluded. inversion more generally. Moreover, we have shown
Indeed, for 24 and 16 bit fixed-point, excluding the - that the computational complexity of the algorithm
factor actually lowers the BER at high SNR in this may be further reduced by almost 20% with minimal
simulation. In addition, the figure shows the benefit impact on the accuracy of the inverted matrix or the
of adopting reduced word size floating-point perceived BER of a BLAST MIMO receiver based
arithmetic—not only due to the resource and upon it.
throughput advantages described in Section II, but
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