scholarly journals Multipath Pipelined Polyphase Structures for FIR Interpolation and Decimation in MIMO OFDM Systems

2011 ◽  
Vol 2011 ◽  
pp. 1-4 ◽  
Author(s):  
Zhen-dong Zhang ◽  
Bin Wu ◽  
Yu-mei Zhou
Keyword(s):  
Data Streams ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Finite Impulse Response ◽  
Multiple Input Multiple Output ◽  
Ofdm Systems ◽  
Silicon Area ◽  
Multiple Data ◽  
Mimo Ofdm ◽  
Multiple Data Streams

The combination of multiple-input multiple-output (MIMO) signal processing with orthogonal frequency-division multiplexing (OFDM) technique is one favored solution in wireless communication systems for enhancing data rate. However, the computational complexity is also linear increased with the number of data streams. Generally, multiple finite impulse response (FIR) interpolations and decimations are added to solve the multiple data streams in a MIMO OFDM system, which cause a large increase in the hardware cost. In this paper, two multipath pipelined polyphase structures for FIR interpolation and decimation to efficiently deal with the simultaneous multiple data streams are proposed. According to the proposed structures, M simultaneous data streams can be supported in the M-component polyphase interpolation or decimation with only one set of computation units. Implementation examples show that up to 56% reduction of silicon area can be obtained over the traditional polyphase structures.

scholarly journals An Efficient Two-Stage Receiver Base on AOR Iterative Algorithm and Chebyshev Acceleration for Uplink Multiuser Massive-MIMO OFDM Systems

Electronics ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 92
Author(s):  
Yung-Ping Tu ◽  
Chih-Yung Chen ◽  
Kuang-Hao Lin
Keyword(s):  
Iterative Algorithm ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Superior Performance ◽  
Ofdm Systems ◽  
Two Stage ◽  
Multiuser Detector ◽  
Input Multiple Output ◽  
Mimo Ofdm

The massive multiple-input multiple-output systems (M-MIMO) and orthogonal frequency-division multiplexing (OFDM) are considered to be some of the most promising key techniques in the emerging 5G and advanced wireless communication systems nowadays. Not only are the benefits of applying M-MIMO and OFDM for broadband communication well known, but using them for the application of the Internet of Things (IoT) requires a large amount of wireless transmission, which is a developing topic. However, its high complexity becomes a problem when there are numerous antennas. In this paper, we provide an effective two-stage multiuser detector (MUD) with the assistance of the accelerated over-relaxation (AOR) iterative algorithm and Chebyshev acceleration for the uplink of M-MIMO OFDM systems to achieve a better balance between bit error rate (BER) performance and computational complexity. The first stage of the receiver consists of an accelerated over-relaxation (AOR)-based estimator and is intended to yield a rough initial estimate of the relaxation factor ω, the acceleration parameter γ, and transmitted symbols. In the second stage, the Chebyshev acceleration method is used for detection, and a more precise signal is produced through efficient iterative estimation. Additionally, we call this proposed scheme Chebyshev-accelerated over-relaxation (CAOR) detection. Conducted simulations show that the developed receiver, with a modest computational load, can provide superior performance compared with previous works, especially in the MU M-MIMO uplink environments.

scholarly journals PAPR Reduction Using Fireworks Search Optimization Algorithm in MIMO-OFDM Systems

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Lahcen Amhaimar ◽  
Saida Ahyoud ◽  
Ali Elyaakoubi ◽  
Abdelmoumen Kaabal ◽  
Kamal Attari ◽  
...  
Keyword(s):  
Computational Complexity ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Papr Reduction ◽  
Main Concern ◽  
Ofdm Systems ◽  
Fireworks Algorithm ◽  
Mimo Ofdm

The transceiver combination technology, of orthogonal frequency division multiplexing (OFDM) with multiple-input multiple-output (MIMO), provides a viable alternative to enhance the quality of service and simultaneously to achieve high spectral efficiency and data rate for wireless mobile communication systems. However, the high peak-to-average power ratio (PAPR) is the main concern that should be taken into consideration in the MIMO-OFDM system. Partial transmit sequences (PTSs) is a promising scheme and straightforward method, able to achieve an effective PAPR reduction performance, but it requires an exhaustive search to find the optimum phase factors, which causes high computational complexity increased with the number of subblocks. In this paper, a reduced computational complexity PTS scheme is proposed, based on a novel swarm intelligence algorithm, called fireworks algorithm (FWA). Simulation results confirmed the adequacy and the effectiveness of the proposed method which can effectively reduce the computation complexity while keeping good PAPR reduction. Moreover, it turns out from the results that the proposed PTS scheme-based FWA clearly outperforms the hottest and most important evolutionary algorithm in the literature like simulated annealing (SA), particle swarm optimization (PSO), and genetic algorithm (GA).

scholarly journals Covert Communication in MIMO-OFDM System Using Pseudo Random Location of Fake Subcarriers

2016 ◽  
Vol 4 (1) ◽  
pp. 150-163 ◽  
Author(s):  
Rizky Pratama Hudhajanto ◽  
I Gede Puja Astawa ◽  
Amang Sudarsono
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Random Sequence ◽  
Multiple Input Multiple Output ◽  
Ofdm System ◽  
Transmission Scheme ◽  
Sensitive Data ◽  
Input Multiple Output ◽  
Mimo Ofdm ◽  
Random Location

Multiple-Input Multiple-Output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) is the most used wireless transmission scheme in the world. However, its security is the interesting problem to discuss if we want to use this scheme to transmit a sensitive data, such as in the military and commercial communication systems. In this paper, we propose a new method to increase the security of MIMO-OFDM system using the change of location of fake subcarrier. The fake subcarriers’ location is generated per packet of data using Pseudo Random sequence generator. The simulation results show that the proposed scheme does not decrease the performance of conventional MIMO-OFDM. The attacker or eavesdropper gets worse Bit Error Rate (BER) than the legal receiver compared to the conventional MIMO-OFDM system.

Factors Influencing the PAPR Performance of OFDM and MIMO-OFDM Systems

2019 ◽  
Vol 11 (3) ◽  
pp. 23-33 ◽  
Author(s):  
Tahreer Mahmood ◽  
Seshadri Mohan
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Channel Fading ◽  
Ofdm Systems ◽  
Practical Applications ◽  
Factors Influencing ◽  
Mimo Ofdm ◽  
Modulation Schemes ◽  
Papr Performance

Multiple-input multiple-output technology together with orthogonal frequency division multiplexing (MIMO-OFDM) is an effective technique to combat multi-channel fading and to improve bandwidth efficiency. Simultaneously, it also increases the system's ability to provide reliable transmission. However, the main disadvantage of OFDM is the high peak-to-average-power ratio (PAPR), which, if not mitigated, will negatively impact practical applications. The high PAPR increases complexity and Bit Error Rate. In this research, the authors investigate the factors influencing the PAPR performance of both OFDM and MIMO-OFDM systems. The objective of this research is to make researchers in this field become familiar with this problem as well as to impart an understanding of the factors that influence PAPR. In this study, the authors classify the factors that impact PAPR into modulation schemes and a number of sub-carriers. These parameters influence the PAPR performance have been analyzed and simulated by using MATLAB. It is observed that the numbers of sub-carriers have a great effect on the PAPR performance. However, modulation schemes can have a small effect on PAPR performance.

Time and Frequency Synchronization for MIMO-OFDM Systems

2013 ◽  
Vol 321-324 ◽  
pp. 2888-2891
Author(s):  
Jing Peng Gao ◽  
Chao Qun Wu ◽  
Dan Feng Zhao
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Carrier Frequency Offset ◽  
Time Synchronization ◽  
Multiple Input Multiple Output ◽  
Frequency Offset ◽  
Time Instant ◽  
Frequency Synchronization ◽  
Ofdm Systems ◽  
Frequency Offset Estimation ◽  
Mimo Ofdm

Any carrier frequency offset will cause a loss of subcarrier orthogonality which results in ICI and hence performance degrades severely in MIMO-OFDM systems. In this paper, a time and frequency synchronization solution for multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems is proposed. The synchronization is achieved using one Constant Amplitude Zero Auto Correlation (CAZAC) sequence-based preamble which is simultaneously transmitted from all transmit antennas in the same OFDM time instant. The synchronization is accomplished sequentially by coarse time synchronization, fractional frequency offset estimation, integral frequency offset estimation and fine time synchronization. The simulation shows that the proposed algorithm can estimate the timing and frequency offsets efficiently in MIMO-OFDM systems, especially in low signal-to-noise ratio condition.

scholarly journals Optimization for Interference Cancellation in MIMO-OFDM System using Modified Bat Algorithm (MBA)

2019 ◽  
Vol 8 (4) ◽  
pp. 24-31
Keyword(s):  
Interference Cancellation ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Bat Algorithm ◽  
Ofdm Systems ◽  
Broadband Wireless ◽  
Multiple Input ◽  
Mimo Ofdm ◽  
Signal Channel ◽  
Modified Bat Algorithm

The intervention has to be negated deprived of humiliation of the spectral effectiveness In broadband wireless communication systems. The intrusive overthrow of the parallel OFDM systems are called as MIMO-OFDM (Multiple Input Output Orthogonal Frequency Division Multiplexing) is brought together in our projected effort. The representation of AWGN within the signal channel and improved by the value of MSE minimum factor is chosen. Thus, the optimization is prepared for the operation of the MBA (Modified Bat Algorithm). Our proposed concepts with its results are evaluated in the platform of MATLAB.

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 Algorithm for Evaluating Energy Detection Spectrum Sensing Performance of Cognitive Radio MIMO-OFDM Systems

Sensors ◽  
2021 ◽  
Vol 21 (20) ◽  
pp. 6881
Author(s):  
Josip Lorincz ◽  
Ivana Ramljak ◽  
Dinko Begusic
Keyword(s):  
Cognitive Radio ◽  
Spectrum Sensing ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Detection Threshold ◽  
Operating Parameter ◽  
Energy Detection ◽  
Operating Parameters ◽  
Ofdm Systems ◽  
Mimo Ofdm

Cognitive radio technology enables spectrum sensing (SS), which allows the secondary user (SU) to access vacant frequency bands in the periods when the primary user (PU) is not active. Due to its minute implementation complexity, the SS approach based on energy detection (ED) of the PU signal has been analyzed in this paper. Analyses were performed for detecting PU signals by the SU in communication systems exploiting multiple-input multiple-output orthogonal frequency division multiplexing (MIMO-OFDM) transmission technology. To perform the analyses, a new algorithm for simulating the ED process based on a square-law combining (SLC) technique was developed. The main contribution of the proposed algorithm is enabling comprehensive simulation analyses of ED performance based on the SLC method for versatile combinations of operating parameter characteristics for different working environments of MIMO-OFDM systems. The influence of a false alarm on the detection probability of PU signals impacted by operating parameters such as the signal-to-noise ratios, the number of samples, the PU transmit powers, the modulation types and the number of the PU transmit and SU receive branches of the MIMO-OFDM systems have been analyzed in the paper. Simulation analyses are performed by running the proposed algorithm, which enables precise selection of and variation in the operating parameters, the level of noise uncertainty and the detection threshold in different simulation scenarios. The presented analysis of the obtained simulation results indicates how the considered operating parameters impact the ED efficiency of symmetric and asymmetric MIMO-OFDM systems.

scholarly journals Downlink Linear Precoders Based on Statistical CSI for Multicell MIMO-OFDM

2017 ◽  
Vol 2017 ◽  
pp. 1-18
Author(s):  
Ebrahim Baktash ◽  
Chi-Heng Lin ◽  
Xiaodong Wang ◽  
Mahmood Karimi
Keyword(s):  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Channel Model ◽  
Matrix Theory ◽  
Covariance Structure ◽  
Optimal Solution ◽  
Closed Form Expression ◽  
Ofdm Systems ◽  
Precoder Design ◽  
Mimo Ofdm

With 5G communication systems on the horizon, efficient interference management in heterogeneous multicell networks is more vital than ever. This paper investigates the linear precoder design for downlink multicell multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems, where base stations (BSs) coordinate to reduce the interference across space and frequency. In order to minimize the overall feedback overhead in next-generation systems, we consider precoding schemes that require statistical channel state information (CSI) only. We apply the random matrix theory to approximate the ergodic weighted sum rate of the system with a closed form expression. After formulating the approximation for general channels, we reduce the results to a more compact form using the Kronecker channel model for which several multicarrier concepts such as frequency selectivity, channel tap correlations, and intercarrier interference (ICI) are rigorously represented. We find the local optimal solution for the maximization of the approximate rate using a gradient method that requires only the covariance structure of the MIMO-OFDM channels. Within this covariance structure are the channel tap correlations and ICI information, both of which are taken into consideration in the precoder design. Simulation results show that the rate approximation is very accurate even for very small MIMO-OFDM systems and the proposed method converges rapidly to a near-optimal solution that competes with networked MIMO and precoders based on instantaneous full CSI.

scholarly journals A Novel Hybrid Block INF Diagonalization (HBID) Precoding Technique for Capacity Improvement in MU-MIMO-OFDM System

2019 ◽  
Vol 9 (1) ◽  
pp. 5369-5375
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Mimo System ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Threshold Value ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Transmission Scheme ◽  
Mimo Ofdm ◽  
Sum Rate

In wireless communication system, the emerging technology is MU-Multiple Input Multiple Output-Orthogonal Frequency Division Multiplexing (MU-MIMO-OFDM). For minimizing Peak-to-Average Power Ratio (PAPR) in the uplink transmission scheme, OFDM is exploited in MIMO system and compared with Single Carrier-Frequency Domain Processing (SC-FDP). Further reducing the PAPR value, a new method is proposed Hybrid Block Inf Diagonalization (HBID) technique for an uplink OFDM system and calculated the less Bit Error Rate (BER). In this paper, the HBID precoding technique reduces PAPR with such amount and unwanted amplitude of the signal is to be cut down for a specific threshold value as 1.4 for best performance so that the PAPR value is reduced in considerable rate of OFDM then compared to SC-FDP system. Also, we compared the various precoding techniques with HBID method in MIMO-OFDM systems with various parameters such as BER, PAPR, Number of users, Sum rate. Finally, the proposed method reduces PAPR with 47% and BER with 50%, number of users with 49% and sum rate as 57%. HBID based precoding method shows its excellence with the lowest PAPR value and thereby enhance the presentation of the OFDM system

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