Architectures for MIMO-OFDM Systems in Frequency-Selective Mobile Fading Channels

Architectures for MIMO-OFDM Systems in Frequency-Selective Mobile Fading Channels

Architectures for MIMO-OFDM Systems in Frequency-Selective Mobile Fading Channels

Abstract:

Orthogonal frequency-division multiplexing (OFDM) is used in third and fourth generation and is being planned for fifth-generation (5G) systems. OFDM requires that the received subcarriers be orthogonal. However, various factors, such as residual carrier frequency offset due to Doppler shift in mobile fading channels, can lead to a loss in orthogonality between subcarriers, which results in intersymbol interference (ISI), intercarrier interference (ICI), and bit error rate (BER) degradation. In developing the conjugate cancelation (CC) scheme for mitigating these ISI and ICI of OFDM systems, we integrate the CC scheme together with a space-time (ST) system and form an STCC multiple-input-multiple-output (MIMO) scheme. This STCC system improves the BER without expending power or bandwidth or complexity. Additionally, a Walsh-Hadamard (WH) transform is employed as a precoder for this STCC system and forms a novel WHSTCC scheme. It provides a low peak-to-average power ratio (PAPR) at the transmitter and a significant diversity gain at the receiver. Simulations indicate that both STCC and WHSTCC schemes outperform the regular CC and ST systems in mobile fading channels. Both schemes are simple and are backward compatible, and they can serve as the baseband building block for reconfigurable 5G multiuser MIMO systems.
Date of Publication: 05 November 2015
ISSN Information:
INSPEC Accession Number: 15634280
Publisher: IEEE

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Conjugate ICI cancellation techniques for 2×1 and 4×1 space-time transmit diversity OFDM systems

Conjugate ICI cancellation techniques for 2×1 and 4×1 space-time transmit diversity OFDM systems

Conjugate ICI cancellation techniques for 2×1 and 4×1 space-time transmit diversity OFDM systems

Abstract:

Orthogonal frequency division multiplexing (OFDM) systems require orthogonality among subcarriers. Unfortunately, the conditions, such as, residual carrier frequency offset, time variations because of Doppler shift or phase noise, which thus destroys the orthogonality at the receiver, hence results in intercarrier interference (ICI) and degrades the bit error rate (BER) performance. In this paper, the conjugate cancellation (CC) to mitigate the ICI of OFDM systems is combined with 2×1 and 4×1 space-time (ST) code to form STCC systems. Even though any full orthogonal transmission matrix is not available, the STCC-OFDM systems with four transmit antennas not only significantly improves the BER of non-orthogonality of the transmission matrix, but also provides a higher transmission rate compared the full orthogonal with the coding rate 0.5 transmissions under the same antenna construction. Furthermore, the error floor provided by 4×1 STCC-OFDM systems with coding rate 1 is significantly lower than the regular CC, ST, and 4×1 ST-OFDM with coding rate 0.5. This STCC-OFDM system may serve as the needed function for the fifth generation (5G) in the multiple-input and multiple-output MIMO-OFDM systems without increasing power, bandwidth, and the computational load.
Date of Conference: 18-21 April 2016
Date Added to IEEE Xplore: 16 June 2016
Electronic ISBN: 978-1-4673-9519-9
INSPEC Accession Number: 16089939
Publisher: IEEE

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SPACE-time and space-frequency OFDM with convolutional precoding over fading channels

SPACE-time and space-frequency OFDM with convolutional precoding over fading channels

SPACE-time and space-frequency OFDM with convolutional precoding over fading channels

Abstract:

Transmit diversity in orthogonal frequency division multiplexing (OFDM) has gained a lot of interest recently due to its ability to transform frequency selective fading into multiple flat fadings. In this paper we investigate 2 transmit and 1 receive (2Tx:1Rx) space-time OFDM (ST-OFDM) and space-frequency OFDM (SF-OFDM) systems in conjunction with convolutional precoding as a redundancy method to combat channel impairments. We built our ST and SF-OFDM on top of our coded OFDM (COFDM) with convolutional coding of rate 1/4 and constraint length of 10. We simulated our ST-OFDM and SF-OFDM over a multipath fading channel using Naftali 802.11 channel model under various delay spreads in relation to outdoor environment. SF-OFDM show a slight performance improvement under these conditions as compared to ST-OFDM by as much as 3 dB signal to noise ratio (SNR) requirement for the same BER of 10−4 for a delay spread of 1.5 microseconds. We also compare our precoded ST-OFDM and SF-OFDM against conventional single carrier OFDM and COFDM systems as well as Alamouti’s space time block code (STBC) system.
Date of Conference: 19-21 Nov. 2008
Date Added to IEEE Xplore: 27 January 2009
ISBN Information:
INSPEC Accession Number: 10469793
Publisher: IEEE

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Architectures for MIMO-OFDM Systems in Frequency-Selective Mobile Fading Channels

Architectures for MIMO-OFDM Systems in Frequency-Selective Mobile Fading Channels

Architectures for MIMO-OFDM Systems in Frequency-Selective Mobile Fading Channels

Abstract:

Orthogonal frequency-division multiplexing (OFDM) is used in third and fourth generation and is being planned for fifth-generation (5G) systems. OFDM requires that the received subcarriers be orthogonal. However, various factors, such as residual carrier frequency offset due to Doppler shift in mobile fading channels, can lead to a loss in orthogonality between subcarriers, which results in intersymbol interference (ISI), intercarrier interference (ICI), and bit error rate (BER) degradation. In developing the conjugate cancelation (CC) scheme for mitigating these ISI and ICI of OFDM systems, we integrate the CC scheme together with a space-time (ST) system and form an STCC multiple-input-multiple-output (MIMO) scheme. This STCC system improves the BER without expending power or bandwidth or complexity. Additionally, a Walsh-Hadamard (WH) transform is employed as a precoder for this STCC system and forms a novel WHSTCC scheme. It provides a low peak-to-average power ratio (PAPR) at the transmitter and a significant diversity gain at the receiver. Simulations indicate that both STCC and WHSTCC schemes outperform the regular CC and ST systems in mobile fading channels. Both schemes are simple and are backward compatible, and they can serve as the baseband building block for reconfigurable 5G multiuser MIMO systems.
Page(s): 1189 – 1193
Date of Publication: 05 November 2015
ISSN Information:
INSPEC Accession Number: 15634280
Publisher: IEEE

What we provide:

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MATLAB, Simulink, MATPOWER, GRIDLAB-D,OpenDSS, ETAP, GAMS

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  • Complete Code of this paper
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  • A document containing complete explanation of code and research approach
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Conjugate ICI cancellation techniques for 2×1 and 4×1 space-time transmit diversity OFDM systems

Conjugate ICI cancellation techniques for 2×1 and 4×1 space-time transmit diversity OFDM systems

Conjugate ICI cancellation techniques for 2×1 and 4×1 space-time transmit diversity OFDM systems

Abstract:

Orthogonal frequency division multiplexing (OFDM) systems require orthogonality among subcarriers. Unfortunately, the conditions, such as, residual carrier frequency offset, time variations because of Doppler shift or phase noise, which thus destroys the orthogonality at the receiver, hence results in intercarrier interference (ICI) and degrades the bit error rate (BER) performance. In this paper, the conjugate cancellation (CC) to mitigate the ICI of OFDM systems is combined with 2×1 and 4×1 space-time (ST) code to form STCC systems. Even though any full orthogonal transmission matrix is not available, the STCC-OFDM systems with four transmit antennas not only significantly improves the BER of non-orthogonality of the transmission matrix, but also provides a higher transmission rate compared the full orthogonal with the coding rate 0.5 transmissions under the same antenna construction. Furthermore, the error floor provided by 4×1 STCC-OFDM systems with coding rate 1 is significantly lower than the regular CC, ST, and 4×1 ST-OFDM with coding rate 0.5. This STCC-OFDM system may serve as the needed function for the fifth generation (5G) in the multiple-input and multiple-output MIMO-OFDM systems without increasing power, bandwidth, and the computational load.
Date of Conference: 18-21 April 2016
Date Added to IEEE Xplore: 16 June 2016
Electronic ISBN: 978-1-4673-9519-9
INSPEC Accession Number: 16089939
Publisher: IEEE

What we provide:

Complete Research Assistance

Technology Involved:-

MATLAB, Simulink, MATPOWER, GRIDLAB-D,OpenDSS, ETAP, GAMS

Deliverables:-  

  • Complete Code of this paper
  • Complete Code of the approach to be propose
  • A document containing complete explanation of code and research approach
  • All materials used for this research
  • Solution to all your queries related to your work