MIMO-OFDM for wireless communications: signal detection with enhanced channel estimation

Li, Y.G.; Winters, J.H.; Sollenberger, N.R.

doi:10.1109/tcomm.2002.802566

Cited by 464 publications

(172 citation statements)

References 21 publications

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“…Winters and N.R.Sollenberger [6] proposed multiple input multiple output (MIMO) devices, data throughput can be increased drastically. Hence MIMO-OFDM systems provide data rate and reliability in wireless communications.…”

Section: Iiliterature Surveymentioning

confidence: 99%

Implementation of High Speed MDC FFT/IFFT Processor for MIMO-OFDM Systems

Basha¹,

L.Suneetha²

2014

IJAREEIE

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ABSTRACT:The architecture of multipath delay commutator (MDC) and memory scheduling are the basic concepts used to implement fast Fourier transform (FFT) processors with variable length. These FFT processors are used in orthogonal frequency division multiplexing systems, having multiple number of inputs and multiple number of outputs. Depending on this MDC architecture, we implement the fft/ifft processor based design which is proposed in this paper. In this design we implement ram, fifo, input buffer and output sorting buffer. The functionality verification and the synthesis is carried out using XILINX ISE 12.3i and shows the reduced delay values. KEYWORDS:Fast Fourier Transform (FFT), memory scheduling, multiple-input and multiple-output (MIMO), orthogonal frequency division multiplexing (OFDM), output sorting, pipeline based multipath delay commutator (MDC), WiMAX. I.INTRODUCTIONWhen we require a data to be encoded at multiple frequencies then the popular scheme generally used is orthogonal frequency division multiplexing. This type of scheme is famous at wideband digital communication. Whether it may be wired or wireless such as television, broadcasting of audio, internet accessing, wireless networks and is widely used in latest technology like 4G mobile communication. Digital multi carrier modulation technique is used for OFDM, When we require to carry parallel streaming of data, a large spaced orthogonal sub-carrier signals are used in which each sub-carrier undergo convolution modulation like quadrature amplitude modulation or phase shift keying. OFDM have capability of channel equalization because it uses slowly modulated narrow band signals instead of using one highly modulated wide band signal. Using OFDM, FFT can be implemented without loss in efficiency. Narrow band co channel interfacing becomes very robust using ofdm .it is very less sensitive over time synchronization errors. These type of OFDM signals have broad range of usage in WLAN under the standard of 802.11a,and digital radio systems standards like DAB/ERUKA 147,Terristial Digital TV systems(DVB-T)and Terrestrial Digital mobile systems(DVB-T) Fast Fourier transform are used to compute discrete Fourier transform and also for its inverse .These technique used to convert to signals from time to frequency domain and vice versa.fft makes numeric algorithm as simple such that it is used in image processing and signal processing applications. In previous DFT is existed ,in which the fastness drawback has overcome by fft.Ofdm uses reverse fft and transmitter side and fft and the receiver side to perform modulation and demodulation efficiently. Fft with ofdm is used cpu like intel Pentium at 1.26GHZ frequency and is able to calculate a 8 192 fft with in 576µs using FFTW, and in cpu called intel Pentium M AT 1.6 GHZ frequency and able to within 387 µs. a compared to earlier generation cpu ,a wide range of fft-ofdm based cpu named intel core 2 duo which operates at3 Ghz frequency and able to perform the operations at 96.MIMO-OFDM defines multi input a...

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Section: Iiliterature Surveymentioning

confidence: 99%

Implementation of High Speed MDC FFT/IFFT Processor for MIMO-OFDM Systems

Basha¹,

L.Suneetha²

2014

IJAREEIE

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“…Since is a hermitian matrix, it can be diagonalized by , where is a unitary matrix and is composed by the eigenvalues of . It is known that can be decomposed as (20) Using the above notations, the residual noise can be written as (22) where is a block diagonal matrix whose diagonal blocks are .…”

Section: Mean Squared Estimation Error (Mse)mentioning

confidence: 99%

“…For example, if any delay is not on the sampling paths, the Fourier transform bases used in [19] and [20] are not the eigenbases of the channel correlation matrix. Depending on the specific channel delay profile that determines , the algorithm may end up with different model error.…”

Section: ) Training Sequence Minimizing the Average Mean Squared Errormentioning

confidence: 99%

Model-based channel estimation framework for MIMO multicarrier communication systems

Wang¹,

Liu

2005

IEEE Trans. Wireless Commun.

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Abstract-The multicarrier modulation (MCM) using multiple antennas is a promising technique for broadband communications over mobile wireless channels. In this work, we investigate the channel estimation problem for the MCM system with multiple transmitter and receiver antennas. The difficulty of such a problem is that the number of the channel parameters increases proportionally with the number of transmitter antennas while the observations at the receiver do not. A model-based channel estimation framework is proposed to identify the multiple channels simultaneously. Based on this framework, we further discuss the identification condition and the training sequence design by taking into account both the model error and residual noise. Finally, we show the performance of the proposed model-based channel estimation scheme using two types of models, Fourier-transform-based model and polynomial model. We also show the system performance of two space-time codes using the proposed channel estimation algorithm. Index Terms-Channel estimation, multicarrier, multiple-input multiple-output (MIMO).

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“…Recently, the combination with OFDM (Orthogonal Frequency Division Multiplexing) technology leads to the MIMO-OFDM technology [3] as a strong candidate for the 4G wireless systems. It is known that the optimal Maximum Likelihood (ML) detector [5] leads to much better performance than the conventional VBLAST algorithm for symbol detection.…”

Section: Introductionmentioning

confidence: 99%

Reduced QRD-M detector in MIMO-OFDM systems with partial and embedded sorting

Guo

McCain

2005

GLOBECOM '05. IEEE Global Telecommunications Conference, 2005.

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Abstract-In this paper,we present a reduced QRD-M matrix symbol detector in MIMO-OFDM systems. The QRD-M algorithm first decomposes the MIMO channel matrix into upper triangular matrix and applies a limited tree search to approximate the maximum-likelihood detector. The metric update is reduced from O(4.5MC) to O(1.5MC) by extracting the commonality. We then propose a partial quick-sort procedure and an embedded insert sort to achieve almost linear sorting. In the second part, we present efficient VLSI architectures utilizing the parallelism between subcarriers and design the pipelining in the multi-stage MIMO processing. The real-time architecture is implemented in a FPGA-based hardware accelerator with compact form factor, which achieves up to 100× speedup in the simulation time.

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MIMO-OFDM for wireless communications: signal detection with enhanced channel estimation

Cited by 464 publications

References 21 publications

Implementation of High Speed MDC FFT/IFFT Processor for MIMO-OFDM Systems

Implementation of High Speed MDC FFT/IFFT Processor for MIMO-OFDM Systems

Model-based channel estimation framework for MIMO multicarrier communication systems

Reduced QRD-M detector in MIMO-OFDM systems with partial and embedded sorting

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