scholarly journals MIMO-OFDM equaliser for spatial multiplexing transmission modes

2010 ◽  
Vol 8 ◽  
pp. 81-85 ◽  
Author(s):  
P. Beinschob ◽  
U. Zölzer
Keyword(s):  
Channel Coding ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Spatial Multiplexing ◽  
Performance Loss ◽  
Low Snr ◽  
Input Multiple Output ◽  
Spatial Interference ◽  
The Impact ◽  
Ber Performance

Abstract. In search for faster and more reliable communication, multiple-input multiple-output (MIMO) in conjuction with Orthogonal Frequency Division Multiplexing (OFDM) are subject of extensive research. In spatial multiplexing transmission an instantaneous rise of data rates governed by the number of transmit antennas can be realised. The system performance depends highly on signal-to-interference-plus-noise ratios (SINR) at the receiver. The receiver's equaliser is supposed to maximize the SINR by mitigating the spatial interference and thus separating the transmitted signals. For this problem several solutions exist such as linear and nonlinear, per subcarrier or OFDM symbol-based. An overview of common algorithms is given and complexity is discussed. Bit error rate (BER) performance evaluations are presented. Another aspect is the impact of the equalisation strategy on the performance of bit-interleaved soft information-based channel coding schemes. As a representative, LDPC codes are chosen. Simulation results show a significant BER performance loss for symbol decision-based equalisers compared to the uncoded performance. To overcome this problem a modification of the Maximum Likelihood algorithm is proposed which yields good performance for low SNR applications.

scholarly journals Phase Noise Effect on MIMO-OFDM Systems with Common and Independent Oscillators

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Xiaoming Chen ◽  
Hua Wang ◽  
Wei Fan ◽  
Yaning Zou ◽  
Andreas Wolfgang ◽  
...  
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Spatial Multiplexing ◽  
Ofdm Systems ◽  
Error Vector Magnitude ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Mimo Ofdm ◽  
Value Decomposition ◽  
Vector Magnitude

The effects of oscillator phase noises (PNs) on multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems are studied. It is shown that PNs of common oscillators at the transmitter and at the receiver have the same influence on the performance of (single-stream) beamforming MIMO-OFDM systems, yet different influences on spatial multiplexing MIMO-OFDM systems with singular value decomposition (SVD) based precoding/decoding. When each antenna is equipped with an independent oscillator, the PNs at the transmitter and at the receiver have different influences on beamforming MIMO-OFDM systems as well as spatial multiplexing MIMO-OFDM systems. Specifically, the PN effect on the transmitter (receiver) can be alleviated by having more transmit (receive) antennas for the case of independent oscillators. It is found that the independent oscillator case outperforms the common oscillator case in terms of error vector magnitude (EVM).

scholarly journals OFDM-Based Generalized Optical MIMO

2020 ◽  
Author(s):  
Chen Chen ◽  
Xin Zhong ◽  
Shu Fu ◽  
Xin Jian ◽  
Min Liu ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
Direct Detection ◽  
Multiple Input Multiple Output ◽  
Detection Algorithm ◽  
Spatial Multiplexing ◽  
Spatial Modulation ◽  
Input Multiple Output ◽  
The Time Domain

<p>The combination of multiple-input multiple-output (MIMO) transmission and orthogonal frequency division multiplexing (OFDM) modulation has been shown to be an effective way to substantially enhance the capacity of bandlimited optical wireless communication (OWC) systems. In this paper, we propose four OFDM-based generalized optical MIMO techniques for intensity modulation/direct detection (IM/DD) OWC systems, including OFDM-based frequency-domain generalized spatial modulation (FD-GSM), frequency-domain generalized spatial multiplexing (FD-GSMP), time-domain generalized spatial modulation (TD-GSM) and time-domain generalized spatial multiplexing (TD-GSMP). For OFDM-based FD-GSM and FDGSMP, spatial mapping is performed in the frequency domain, while it is carried out in the time domain for OFDM-based TDGSM and TD-GSMP. To efficiently estimate both spatial and constellation symbols in each OFDM-based generalized optical MIMO technique, a corresponding maximum-likelihood (ML) detection algorithm is designed. Extensive simulations are conducted to evaluate and compare the performance of the proposed four OFDM-based generalized optical MIMO techniques in a typical indoor environment. Simulation results demonstrate the superiority of OFDM-based TD-GSM and TD-GSMP for various spectral efficiencies of 4, 5 and 6 bits/s/Hz, when a relatively high secondary direct current (DC) bias is adopted.</p>

scholarly journals OFDM-Based Generalized Optical MIMO

2020 ◽  
Author(s):  
Chen Chen ◽  
Xin Zhong ◽  
Shu Fu ◽  
Xin Jian ◽  
Min Liu ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
Direct Detection ◽  
Multiple Input Multiple Output ◽  
Detection Algorithm ◽  
Spatial Multiplexing ◽  
Spatial Modulation ◽  
Input Multiple Output ◽  
The Time Domain

<p>The combination of multiple-input multiple-output (MIMO) transmission and orthogonal frequency division multiplexing (OFDM) modulation has been shown to be an effective way to substantially enhance the capacity of bandlimited optical wireless communication (OWC) systems. In this paper, we propose four OFDM-based generalized optical MIMO techniques for intensity modulation/direct detection (IM/DD) OWC systems, including OFDM-based frequency-domain generalized spatial modulation (FD-GSM), frequency-domain generalized spatial multiplexing (FD-GSMP), time-domain generalized spatial modulation (TD-GSM) and time-domain generalized spatial multiplexing (TD-GSMP). For OFDM-based FD-GSM and FDGSMP, spatial mapping is performed in the frequency domain, while it is carried out in the time domain for OFDM-based TDGSM and TD-GSMP. To efficiently estimate both spatial and constellation symbols in each OFDM-based generalized optical MIMO technique, a corresponding maximum-likelihood (ML) detection algorithm is designed. Extensive simulations are conducted to evaluate and compare the performance of the proposed four OFDM-based generalized optical MIMO techniques in a typical indoor environment. Simulation results demonstrate the superiority of OFDM-based TD-GSM and TD-GSMP for various spectral efficiencies of 4, 5 and 6 bits/s/Hz, when a relatively high secondary direct current (DC) bias is adopted.</p>

scholarly journals The Analysis of Mobile WiMAX and LTE using MIMO technique

2013 ◽  
Vol 5 (1) ◽  
pp. 35-40
Author(s):  
Roopali Garg ◽  
Shafi Singla
Keyword(s):  
Channel Coding ◽  
Multiple Input Multiple Output ◽  
Spatial Multiplexing ◽  
Mobile Wimax ◽  
Ieee 802.16E ◽  
File Transfer ◽  
Network Resources ◽  
Multiple Input ◽  
Input Multiple Output

A quality of service is a fundamental component of the 4G broadband network for satisfactory service delivery by evolving internet application to end user, and managing the network resources. The 4G technology has emerged one of the most fruitful technologies as it supports large number of applications including VOIP, video conferencing, file transfer, video streaming and web browsing. IEEE 802.16E, IEEE 802.16M and LTE along with various application and QoS requirement also support Multiple-Input-multiple-output (MIMO) techniques including Spatial Multiplexing (SM), Space Time Block Coding(STBC) and Eigen Beam-forming (BM).In the paper we will study Physical, MAC layer of WiMAX and LTE. We will also study MIMO techniques. In this paper  the detailed study of the throughput for a MIMO mobile WiMAX system and LTE  under two different PHY PER QoS threshold. Various modulation and channel coding techniques have been applied.

Novel User Scheduling Schemes Based on Nonlinear Precoding for Multiuser MIMO Systems

2012 ◽  
Vol 195-196 ◽  
pp. 270-276 ◽  
Author(s):  
Cun Yi Zhang ◽  
Mu Qing Wu ◽  
Run Qian Chen ◽  
Guo Dong Ma
Keyword(s):  
Mimo Systems ◽  
Geometric Mean ◽  
Multiple Input Multiple Output ◽  
Computation Complexity ◽  
User Scheduling ◽  
Processing Scheme ◽  
Scheme Design ◽  
Input Multiple Output ◽  
The Impact ◽  
Ber Performance

This paper proposes a novel greedy user ordering algorithm for the multiuser multiple-input multiple-output (MIMO) systems employing block diagonal geometric mean decomposition method and Tomlinson-Harashima precoding (THP). Theoretical analysis and computer simulations illustrate its low computation complexity relative to the optimal user ordering achieving by brute search over all the possible ordering permutations resulting in extremely high computation complexity. Meanwhile the bit error rate (BER) performance of the proposed algorithm is very close to the optimal user ordering. Moreover, in order to mitigate the impact of users with smaller sub-channel gains to the whole systems BER performance, a joint pre-processing scheme design of adaptive data streams reduction and greedy user ordering (ADSR-GUO) is proposed. By means of choosing different values for the controlling factor, we can obtain different system sum-rate and BER performance to satisfy different quality-of-service (QoS) requirements.

A companding approach for PAPR suppression in OFDM based massive MIMO system

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Ajay Kumar Yadav ◽  
Pritam Keshari Sahoo ◽  
Yogendra Kumar Prajapati
Keyword(s):  
Massive Mimo ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Base Station ◽  
Convex Optimization Problem ◽  
Multiple Input ◽  
Input Multiple Output ◽  
Mimo Ofdm

Abstract Orthogonal frequency division multiplexing (OFDM) based massive multiuser (MU) multiple input multiple output (MIMO) system is popularly known as high peak-to-average power ratio (PAPR) issue. The OFDM-based massive MIMO system exhibits large number of antennas at Base Station (BS) due to the use of large number of high-power amplifiers (HPA). High PAPR causes HPAs to work in a nonlinear region, and hardware cost of nonlinear HPAs are very high and also power inefficient. Hence, to tackle this problem, this manuscript suggests a novel scheme based on the joint MU precoding and PAPR minimization (PP) expressed as a convex optimization problem solved by steepest gradient descent (GD) with μ-law companding approach. Therefore, we develop a new scheme mentioned to as MU-PP-GDs with μ-law companding to minimize PAPR by compressing and enlarging of massive MIMO OFDM signals simultaneously. At CCDF = 10−3, the proposed scheme (MU-PP-GDs with μ-law companding for Iterations = 100) minimizes the PAPR to 3.70 dB which is better than that of MU-PP-GDs, (iteration = 100) as shown in simulation results.

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