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The MIMO system convincingly promises a better bit rate in comparison with a SISO system. The system gets even efficient when OFDM is implemented with MIMO to obtain better data rates even in hostile channel environment. Research establishes OFDM as a potential candidate for use in MIMO systems for the reasons like inherent FFT, waveform adaptation, advanced antenna techniques, multiple access, interoperability,...
The MIMO system convincingly promises a better bit rate in comparison with a SISO system. The system gets even efficient when OFDM is amalgamated with MIMO to obtain better data rates even in hostile channel environment. Research establishes OFDM as a potential candidate for use in MIMO systems for the reasons like inherent FFT, waveform adaptation, advanced antenna techniques, multiple access, interoperability,...
The Fourth generation (4G) wireless networks are expected to afford high data rate transmission of multimedia services such as wireless video, wireless Internet access and mobile computing. Orthogonal frequency division multiplexing (OFDM) is an effective technique for the future 4G communications because of its great immunity to impulse noise and intersymbol interference. Ultra wide band (UWB) wireless...
Machine learning algorithms have recently attracted much interest for effective link adaptation due to their flexibility and ability to capture more environmental effects implicitly than classical adaptation algorithms. However, past applications are limited to rather simple configurations such as identifying channel condition or link adaptation in fixed or slowly varying channels. Recently, more...
We investigate non-coherent multi-input multi-output (MIMO) signal processing which requires no channel state information (CSI) at either the transmitter or the receiver. With non-coherent codes on Grassmann manifold, a receiver employing generalized likelihood ratio test (GLRT) algorithm offers the maximum-likelihood performance even without CSI. However, the conventional GLRT suffers from a severe...
In this contribution, a multi-user receiver for M-QAM MIMO-OFDM operating in time-varying and frequency-selective channels is derived. The proposed architecture jointly performs semi-blind estimation of the channel weights and noise inverse variance, serial interference cancellation and decoding in an iterative manner. The scheme relies on a variational message-passing approach, which enables a joint...
This paper presents a low-complexity architecture compensating for carrier frequency offset (CFO) and IQ imbalance circuits in MIMO-OFDM receiver systems. A coordinate rotation digital computer based sinusoid iteration generator is also developed for CFO estimation and correction in wireless communication receivers. Besides the main effect from the multi-path, some non-ideal effects from imperfect...
This paper presents a MIMO-OFDM baseband transceiver design for indoor gigabit wireless communication systems. The proposed system uses 5 GHz carrier frequency with bandwidth up to 160 MHz. Both the transmitter and the receiver support 4 antennas. At the receiver, we design symbol timing detector, carrier frequency offset first acquisition and subsequent tracking mechanisms, channel estimation and...
In the MIMO-OFDM system, the carrier frequency offset and phase noise cause loss of orthogonality among subcarriers and leads to intercarrier interference (ICI). This paper considers ICI self-cancellation schemes using space frequency block code (SFBC) in MIMO-OFDM system. In this paper we have analytically derived expression for common phase error (CPE), ICI, carrier to interference (CIR) and BER...
Linear precoding plays an important role in the spatial multiplexing multiple-input multiple-output (MIMO)-orthogonal frequency-division multiplexing (OFDM) systems which are considered one of the primary candidates for the physical-layer techniques in the next-generation wireless communication systems. It requires the channel state information (CSI) at the transmitter to adapt the transmitted signal...
In this paper, we propose a feedback algorithm based on the B-spline models of channel responses(CRs) variation across subchannels. We determine the coefficients of the B-splines based on the least-squares fitting principle. The coefficients of the B-splines are fed back to the transmitter for the CRs reconstruction. In the feedback process, we also apply efficient quantization algorithms based on...
Performances and capacity of MIMO-OFDM systems are enhanced with adaptive MIMO techniques such as Demmel condition number based switching algorithm. In this paper we show that the complexity of this algorithm can be reduced by using the 2-norm condition number of the channel matrix as the selection metric. Simulation results show that using this selection criterion, the switching algorithm offers...
Recently, the LTE (Long Term Evolution) and LTE-Advanced systems, developed by the 3GPP (Third Generation Partnership Project), has been proposed as the candidate for the 4G systems (forth mobile communication systems). The combination of OFDM (orthogonal frequency division multiplexing) and MIMO (multiple-input multiple-output) transmission technologies has been introduced into LTE systems for achieving...
In this paper we analyze the distribution of effective Signal-to-Interference-plus-Noise-Ratio (SINR) in multiple input multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) systems with application to 3GPP Long Term Evolution (LTE) Downlink. The asymptotic distribution of effective SINR in case of correlated post-processed SINR is established analytically to obey normal distribution...
Multiple-input multiple-output (MIMO) communications based on orthogonal frequency division multiplexing (OFDM) are considered for improving the performance and bandwidth utilization of underwater acoustic systems in which cooperation is possible between distributed transmitters. The major challenge in such a framework - and the principal difference from the traditional case where multiple transmitters...
MIMO-OFDM has been actively studied for high data rate communications over the bandwidth-limited underwater acoustic (UWA) channels. Unlike existing receivers that treat the intercarrier interference (ICI) as additive noise, in this paper we deal with ICI explicitly together with the co-channel interference (CCI) due to parallel transmissions in MIMO-OFDM. The proposed receiver has the following components:...
For single-carrier systems with frequency domain equalization, decision feedback equalization (DFE) performs better than linear equalization, and has a lower complexity and computational costs than optimum equalizers. The main challenge in DFE is the feedback symbol selection rule. In this paper, we give a theoretical framework for a simple, sparsity based thresholding algorithm. We feedback multiple...
In this paper we design high performance multiple-input-multiple-output (MIMO) receivers for the DFT-Spread-OFDM based long term evolution (LTE) cellular uplink. In the LTE uplink multiple single-antenna users can be scheduled on the same time-frequency resource block via space division multiple access. The designed receivers are also applicable to the LTE-Advanced cellular uplink wherein simultaneous...
In this paper, we propose a sum rate maximizing ordering method for hard decision successive interference cancellation receiver of MIMO-OFDM systems. Compared with conventional ordering methods developed for open loop MIMO systems, the proposed scheme shows considerable improvement in throughput capacity. We propose two simplified methods with considerable complexity reduction and negligible performance...
Closed-loop transmission combined with MIMO (multiple-input multiple-output) and OFDM (orthogonal frequency division multiplexing) technologies have drawn most attentions during development of the 4G systems (fourth generation of mobile communication systems). In LTE (Long Term Evolution) and LTE-Advanced systems, which are proposed by 3GPP (Third Generation Partnership Project) to be the most competitive...
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