scholarly journals A Hybrid Multiuser Detector Based on MMSE and AFSA for TDRS System Forward Link

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Zhendong Yin ◽  
Xu Jiang ◽  
Zhilu Wu ◽  
Xiaohui Liu
Keyword(s):  
Global Convergence ◽  
Multiuser Detection ◽  
Minimum Mean Square Error ◽  
Low Complexity ◽  
System Capacity ◽  
Forward Link ◽  
Artificial Fish Swarm Algorithm ◽  
Multiuser Detector ◽  
Error Ratio ◽  
Bit Error Ratio

This study mainly focuses on multiuser detection in tracking and data relay satellite (TDRS) system forward link. Minimum mean square error (MMSE) is a low complexity multiuser detection method, but MMSE detector cannot achieve satisfactory bit error ratio and near-far resistance, whereas artificial fish swarm algorithm (AFSA) is expert in optimization and it can realize the global convergence efficiently. Therefore, a hybrid multiuser detector based on MMSE and AFSA (MMSE-AFSA) is proposed in this paper. The result of MMSE and its modified formations are used as the initial values of artificial fishes to accelerate the speed of global convergence and reduce the iteration times for AFSA. The simulation results show that the bit error ratio and near-far resistance performances of the proposed detector are much better, compared with MF, DEC, and MMSE, and are quite close to OMD. Furthermore, the proposed MMSE-AFSA detector also has a large system capacity.

Novel Scheme for Multiple-Access Interference Mitigation with Low Complexity

2011 ◽  
Vol 143-144 ◽  
pp. 371-375
Author(s):  
Zuo Liang Yin ◽  
Hui Xiao Ma ◽  
Xing Peng Mao ◽  
Jun Cai
Keyword(s):  
Multiple Access ◽  
Interference Mitigation ◽  
Multiple Access Interference ◽  
Low Complexity ◽  
System Capacity ◽  
Error Performance ◽  
Multiuser Detector ◽  
Access Scheme ◽  
Lower Complexity

To mitigate multiple access interference and improve the system capacity, an effective multiple access scheme, called GCDMA, is proposed. Exploiting the IDMA iterative multiuser detector in each group, the intra-group interference can be effectively handled. Analysis and simulations demonstrate that the proposed technique outperforms the conventional CDMA in terms of both system capacity and bit error performance. Lower complexity of the proposed scheme can be achieved than CDMA and even IDMA.

scholarly journals Low-complexity sparse-aware multiuser detection for large-scale MIMO systems

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
Rong Ran ◽  
Hayoung Oh
Keyword(s):  
Large Scale ◽  
Mimo Systems ◽  
Minimum Mean Square Error ◽  
Multiple Input Multiple Output ◽  
Low Complexity ◽  
Finite Alphabet ◽  
Multiuser Detectors ◽  
Input Multiple Output ◽  
Error Detector ◽  
Significant Performance

AbstractSparse-aware (SA) detectors have attracted a lot attention due to its significant performance and low-complexity, in particular for large-scale multiple-input multiple-output (MIMO) systems. Similar to the conventional multiuser detectors, the nonlinear or compressive sensing based SA detectors provide the better performance but are not appropriate for the overdetermined multiuser MIMO systems in sense of power and time consumption. The linear SA detector provides a more elegant tradeoff between performance and complexity compared to the nonlinear ones. However, the major limitation of the linear SA detector is that, as the zero-forcing or minimum mean square error detector, it was derived by relaxing the finite-alphabet constraints, and therefore its performance is still sub-optimal. In this paper, we propose a novel SA detector, named single-dimensional search-based SA (SDSB-SA) detector, for overdetermined uplink MIMO systems. The proposed SDSB-SA detector adheres to the finite-alphabet constraints so that it outperforms the conventional linear SA detector, in particular, in high SNR regime. Meanwhile, the proposed detector follows a single-dimensional search manner, so it has a very low computational complexity which is feasible for light-ware Internet of Thing devices for ultra-reliable low-latency communication. Numerical results show that the the proposed SDSB-SA detector provides a relatively better tradeoff between the performance and complexity compared with several existing detectors.

Research on the Technology of Low-Voltage Power Line Carrier-Current Communication Based on OFDM

2013 ◽  
Vol 397-400 ◽  
pp. 2004-2007
Author(s):  
Wen Yan Ding ◽  
Zhi Ning Sun ◽  
Xiang Long Wang
Keyword(s):  
Low Voltage ◽  
Power Line ◽  
Power Line Communication ◽  
Channel Code ◽  
Carrier Wave ◽  
Wave Modulation ◽  
Modulation And Demodulation ◽  
Error Ratio ◽  
Power Line Carrier ◽  
Bit Error Ratio

The design on the system of low-voltage power line carrier-current communication based on OFDM was finished in this paper. Then model of the system was simulated and the modulation and demodulation of OFDM were realized. The results show that the integral performance can be enhanced with channel code. And the bit error ratio (BER) of the system is different with several sub-carrier wave modulation modes. This system could satisfy the requirement of power line communication basically.

scholarly journals Improvement of Multipath Channel Performance for Optical MIMO-OFDM in LED Modulation with Fully Generalized Spatial-Frequency

2021 ◽  
Author(s):  
Nandhini Devi R ◽  
Leones Sherwin VimalrajS ◽  
Lydia J
Keyword(s):  
Optical Communication ◽  
Spatial Multiplexing ◽  
Modulation Scheme ◽  
New Concepts ◽  
Data Rates ◽  
Error Ratio ◽  
Bit Error Ratio ◽  
Mimo Ofdm ◽  
Transmission Diversity ◽  
Ofdm Signals

This paper suggests a scheme to generalize the idea of LED index modulation concept by using the spatial multiplexing principle to relay complex OFDM signals through various channels such as AWGN, Rayleigh and Rician by splitting these signals into their real-imaginary and positive-negative components. In order to combat ISI as well as to increase the channel capacity. The MIMO-OFDM efficiency analysis, taking into account the constraint of the forward current of the LED is extracted. The accuracy of the theoretical results is verified by comparing the Bit Error Ratio (BER) reduction and improvement to the (SNR) results under varying condition of the channel. Using MIMO-OFDM as next-generation techniques, along with QAM aims to provide development of new concepts that will lead to the growth of future optical communication. Simulation results validate data rates gained over optical communication using LED modulation scheme and the pure transmission diversity method.

scholarly journals Eigenvalue Decomposition Precoded Faster-Than-Nyquist Transmission of Index Modulated Symbols

2021 ◽  
Author(s):  
Prakash Chaki ◽  
Takumi Ishihara ◽  
Shinya Sugiura
Keyword(s):  
Time Domain ◽  
Eigenvalue Decomposition ◽  
Single Carrier ◽  
Error Ratio ◽  
Nyquist Criterion ◽  
Bit Error Ratio ◽  
Personal Use ◽  
Constrained Capacity ◽  
Criterion Time ◽  
Ieee International Symposium

Postprint accepted on 30 April 2021 for publication in IEEE International Symposium on Information Theory (ISIT), 2021. (c) 2021 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.<div>In this paper, we propose a precoded faster-than-Nyquist (FTN) signaling technique for time-domain single-carrier index modulated (IM) symbol transmission. More precisely, eigenvalue decomposition precoding is adopted for the FTN transmission of data bits modulated by single-carrier time-domain IM. While the FTN scheme increases the spectral efficiency and data rate by packing more transmit symbols per block duration than those defined in the Nyquist criterion, time-domain IM works towards the same objective while maintaining symbol sparsity. We analytically derive the constrained capacity of the proposed system. Our simulation results show that the proposed scheme has better bit error ratio (BER) performance over the conventional FTN-IM scheme, particularly for the scenario of a higher packing ratio. In the proposed scheme, $2.5$-dB performance gain is observed at the BER of 10<sup>-4</sup>, employing the packing ratio of $0.7$ and the roll-off factor of $0.5$ in a channel-uncoded scenario.<br></div>

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