scholarly journals Characterization of Path-Loss Disparity in Virtual Multiple-Input-Single-Output Links

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Haejoon Jung ◽  
Mary Ann Weitnauer
Keyword(s):  
Antenna Array ◽  
Signal To Noise Ratio ◽  
Multiple Input Multiple Output ◽  
Path Loss ◽  
Spatial Diversity ◽  
Cooperative Transmission ◽  
Single Output ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Log Normal

Cooperative transmission (CT) is an effective technique to achieve spatial diversity in fading environments, where spatially separated wireless nodes collaborate to form a virtual antenna array or virtual multiple-input-multiple-output (VMISO) link. Many authors model the path loss of the VMISO link as though the elements in the virtual antenna array are colocated, even though they are spread out. In this paper, we show that the spreading causes a signal-to-noise-ratio (SNR) penalty of up to 3 dB. Moreover, in the high SNR regime, we show that the performance degradation caused by the path-loss disparity can be characterized equivalently by log-normal distribution. We use these two observations to propose a new CT link model, expressed in closed form as an outage probability based on the log-normal shadowing model. The quality of the model is evaluated by a statistical test based on Kolmogorov-Smirnov method.

scholarly journals The BER Analysis of MIMO System for M-PSK over Different Fading Channels using STBC Code Structure

2019 ◽  
Vol 8 (3) ◽  
pp. 5831-5836
Keyword(s):  
Fading Channels ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Spatial Diversity ◽  
Single Input Single Output ◽  
Single Output ◽  
Code Structure ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Rician Channel

High information rates inside the restricted frequency (RF) spectrum is often fascinating that results in radios with capabilities on the far side a single-input single-output (SISO) topology. In recent days introduced wireless systems have adopted multiple-input multiple-output (MIMO) topologies that use 2 or more transmitters and 2 or more receivers to send information at the same time over same RF bandwidth. The performance of MIMO system may be improved by involving multiple antennas at transmitter and receiver therefore on offer spatial diversity. during this paper, the performance analysis of MIMO system over AWGN attenuation channel and Rician Channel with ZF receiver is bestowed. The consequences of the antenna choice can even be analyzed from the simulated results. The BER (Bit Error Rate) performance characteristics of ZeroForcing (ZF) receiver is investigated for M-PSK modulation technique over the AWGN channel and Rician Channel.

scholarly journals MIMO Self-Encoded Spread Spectrum with Iterative Detection over Rayleigh Fading Channels

2010 ◽  
Vol 2010 ◽  
pp. 1-9 ◽  
Author(s):  
Shichuan Ma ◽  
Lim Nguyen ◽  
Won Mee Jang ◽  
Yaoqing (Lamar) Yang
Keyword(s):  
Fading Channels ◽  
Spread Spectrum ◽  
Rayleigh Fading ◽  
Mimo Systems ◽  
Signal To Noise Ratio ◽  
Multiple Input Multiple Output ◽  
Spatial Diversity ◽  
Iterative Detection ◽  
Channel Fading ◽  
Input Multiple Output

Self-encoded spread spectrum (SESS) is a novel communication technique that derives its spreading code from the randomness of the source stream rather than using conventional pseudorandom noise (PN) code. In this paper, we propose to incorporate SESS in multiple-input multiple-output (MIMO) systems as a means to combat against fading effects in wireless channels. Orthogonal space-time block-coded MIMO technique is employed to achieve spatial diversity, and the inherent temporal diversity in SESS modulation is exploited with iterative detection. Simulation results demonstrate that MIMO-SESS can effectively mitigate the channel fading effect such that the system can achieve a bit error rate of with very low signal-to-noise ratio, from 3.3 dB for a antenna configuration to just less than 0 dB for a configuration under Rayleigh fading. The performance improvement for the case is as much as 6.7 dB when compared to an MIMO PN-coded spread spectrum system.

scholarly journals Adaptive Threshold-Aided K-Best Sphere Decoding for Large MIMO Systems

2019 ◽  
Vol 9 (21) ◽  
pp. 4624
Author(s):  
Uzokboy Ummatov ◽  
Kyungchun Lee
Keyword(s):  
Mimo Systems ◽  
Signal To Noise Ratio ◽  
Multiple Input Multiple Output ◽  
Threshold Value ◽  
Adaptive Threshold ◽  
Sphere Decoding ◽  
High Signal ◽  
Signal To Noise ◽  
Multiple Input ◽  
Input Multiple Output

This paper proposes an adaptive threshold-aided K-best sphere decoding (AKSD) algorithm for large multiple-input multiple-output systems. In the proposed scheme, to reduce the average number of visited nodes compared to the conventional K-best sphere decoding (KSD), the threshold for retaining the nodes is adaptively determined at each layer of the tree. Specifically, we calculate the adaptive threshold based on the signal-to-noise ratio and index of the layer. The ratio between the first and second smallest accumulated path metrics at each layer is also exploited to determine the threshold value. In each layer, in addition to the K paths associated with the smallest path metrics, we also retain the paths whose path metrics are within the threshold from the Kth smallest path metric. The simulation results show that the proposed AKSD provides nearly the same bit error rate performance as the conventional KSD scheme while achieving a significant reduction in the average number of visited nodes, especially at high signal-to-noise ratios.

scholarly journals Nearest Neighbor Decoding and Pilot-Aided Channel Estimation for Fading Channels

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 971
Author(s):  
A. Taufiq Asyhari ◽  
Tobias Koch ◽  
Albert Guillén i Fàbregas
Keyword(s):  
Channel Estimation ◽  
Fading Channels ◽  
Multiple Access ◽  
Nearest Neighbor ◽  
Signal To Noise Ratio ◽  
Multiple Input Multiple Output ◽  
Comparative Performance ◽  
Single Output ◽  
Multiple Input ◽  
Flat Fading

We study the information rates of noncoherent, stationary, Gaussian, and multiple-input multiple-output (MIMO) flat-fading channels that are achievable with nearest neighbor decoding and pilot-aided channel estimation. In particular, we investigate the behavior of these achievable rates in the limit as the signal-to-noise ratio (SNR) tends to infinity by analyzing the capacity pre-log, which is defined as the limiting ratio of the capacity to the logarithm of the SNR as the SNR tends to infinity. We demonstrate that a scheme estimating the channel using pilot symbols and detecting the message using nearest neighbor decoding (while assuming that the channel estimation is perfect) essentially achieves the capacity pre-log of noncoherent multiple-input single-output flat-fading channels, and it essentially achieves the best so far known lower bound on the capacity pre-log of noncoherent MIMO flat-fading channels. Extending the analysis to fading multiple-access channels reveals interesting relationships between the number of antennas and Doppler bandwidth in the comparative performance of joint transmission and time division multiple-access.

DESIGN AND MEASUREMENTS OF A MULTIPLE-OUTPUT TRANSMITTER FOR MIMO APPLICATIONS

2011 ◽  
Vol 20 (03) ◽  
pp. 515-529 ◽  
Author(s):  
CONSTANTINOS I. VOTIS ◽  
PANOS KOSTARAKIS ◽  
LEONIDAS P. IVRISSIMTZIS
Keyword(s):  
Antenna Array ◽  
Beam Steering ◽  
Multiple Input Multiple Output ◽  
Direct Digital Synthesis ◽  
Digital Beamforming ◽  
Channel Sounder ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Digital Synthesis ◽  
Array Performance

The design of a multiple-output transmitter for digital beamforming (DBF), Multiple-Input Multiple-Output (MIMO) and channel sounder applications, based on Direct Digital Synthesis (DDS) system is presented and investigated in terms of antenna array performance. DDS generates independently modulated signals on specific carrier frequencies and is employed as the first stage in the proposed implementation, furnishing output signal of configurable amplitude, phase and frequency. The resulting phase progression, amplitude and beamforming accuracy of a beam steering array are further investigated, showing that the proposed architecture can provide a steering beam with high accuracy. Experimental results of system performance indicate that this architecture can drive efficiently and accurately an antenna array with independent modulated RF signals, with programmable frequency, initial phase, and magnitude.

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