scholarly journals Synchronization in MIMO OFDM systems

2005 ◽  
Vol 2 ◽  
pp. 147-153 ◽  
Author(s):  
L. Häring ◽  
A. Czylwik
Keyword(s):  
Carrier Frequency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Carrier Frequency Offset ◽  
Mimo Systems ◽  
Multiple Input Multiple Output ◽  
High Sensitivity ◽  
Ofdm Systems ◽  
Single Input Single Output ◽  
Input Multiple Output ◽  
Single Input

Abstract. In this paper, an overview of carrier frequency offset (CFO) estimation algorithms for Orthogonal Frequency Division Multiplexing (OFDM) systems is presented. It is well-known that multicarrier systems suffer from their high sensitivity to mismatches of transmitter and receiver oscillator frequencies. The performance degrades since the CFO destroys the orthogonality of the subcarriers. Hence, extensive research has been done on the estimation and correction of the CFO in Single-Input Single-Output (SISO) systems. Mainly, the proposed algorithms can be categorized into data-aided and blind techniques. Several estimation techniques have been extended to the Single-Input Multiple- Output (SIMO) case where multiple receive antennas can be utilized to gain diversity. However, less attention has been paid on synchronization in the attractive Multiple-Input Multiple-Output (MIMO) case which is topic of tremendous interest in current research. The present paper concentrates on aspects of this new scenario. Starting with algorithms for SISO and SIMO, this contribution reviews briefly proposed carrier frequency synchronization techniques which could be implemented in forthcoming MIMO systems.

scholarly journals The Analysis of the Effect and Reduction of Carrier Frequency Offset in Orthogonal Frequency Division Multiplexing (OFDM) Multiple Input Multiple Output (MIMO)

2020 ◽  
Vol 19 (2) ◽  
pp. 219
Author(s):  
Willy Sucipto ◽  
I Nyoman Pramaita ◽  
NMAE Dewi Wirastuti
Keyword(s):  
Carrier Frequency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Pulse Shaping ◽  
Carrier Frequency Offset ◽  
Multiple Input Multiple Output ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
A Value ◽  
Multiple Input ◽  
Input Multiple Output

Abstract— The development of cellular telecommunication provides users to experience fast and stable transmission. This standard of transmission is proportional to the needs of the devices and systems used. We are currently in the fourth generation (4G) of cellular technology. The key technologies used in 4G are Orthogonal Frequency Division Multiplexing (OFDM) which uses the concept of orthogonality for bandwidth efficiency and Multiple Input Multiple Output (MIMO) which uses the concept of diversity to improve performance. But in implementation this system will have problems with the transmission channel. The problem that occurs is signal attenuation due to Carrier Frequency Offset (CFO). This CFO will cause the orthogonal character built from the OFDM system to experience a decline in performance. The decline in performance is due to the occurrence of Intercarrier Interference (ICI). To overcome this problem, the method used in this simulation are Improved Sinc Power Pulse (ISP) and Rectangular Pulse (REC). The results showed that ISP had a relatively better BER value than REC and without using the pulse shaping method. The minimum BER value obtained from the simulation is ISP with a value of 0.0001 while REC produces a value of 0.0006 and without pulse shaping produces a BER value of 0.0038.

scholarly journals A Survey on Massive MIMO Systems in Presence of Channel and Hardware Impairments

Sensors ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 164 ◽  
Author(s):  
Zahra Mokhtari ◽  
Maryam Sabbaghian ◽  
Rui Dinis
Keyword(s):  
Massive Mimo ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mimo Systems ◽  
Low Cost ◽  
Multiple Input Multiple Output ◽  
Base Station ◽  
Aging Effects ◽  
Hardware Impairments ◽  
Single Carrier ◽  
Input Multiple Output

Massive multiple input multiple output (MIMO) technology is one of the promising technologies for fifth generation (5G) cellular communications. In this technology, each cell has a base station (BS) with a large number of antennas, allowing the simultaneous use of the same resources (e.g., frequency and/or time slots) by multiple users of a cell. Therefore, massive MIMO systems can bring very high spectral and power efficiencies. However, this technology faces some important issues that need to be addressed. One of these issues is the performance degradation due to hardware impairments, since low-cost RF chains need to be employed. Another issue is the channel estimation and channel aging effects, especially in fast mobility environments. In this paper we will perform a comprehensive study on these two issues considering two of the most promising candidate waveforms for massive MIMO systems: Orthogonal frequency division multiplexing (OFDM) and single-carrier frequency domain processing (SC-FDP). The studies and the results show that hardware impairments and inaccurate channel knowledge can degrade the performance of massive MIMO systems extensively. However, using suitable low complex estimation and compensation techniques and also selecting a suitable waveform can reduce these effects.

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 Peak Average Power Ratio Reduction Technique for Better Performance with Multi Input Multi Output

2019 ◽  
Vol 8 (6S) ◽  
pp. 199-202
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Average Power ◽  
Reduction Technique ◽  
Papr Reduction ◽  
Power Ratio ◽  
Ofdm Systems ◽  
Reduction Techniques ◽  
Input Multiple Output ◽  
Power Ratio Reduction

In the transmitted signal, the high peak-toaverage power ratio (PAPR) is the real disadvantage of multiple input, multiple output (MIMO) orthogonal frequency division multiplexing (OFDM) systems. Among different PAPR reduction techniques, selected mapping (SLM) is a famous strategy that accomplishes good PAPR reduction performance without signal distortion. Likewise, Partial transmit sequence (PTS) is additionally solitary of the successful techniques to decrease the PAPR in OFDM. Though, result an optimal segment issue in PTS system is measured to exist a critical concern. To progress the existing PAPR reduction techniques, we have incorporated ideal SLM and PTS based PAPR reduction strategy in parallel. By utilizing, the OGWO algorithm; the transmit succession was chosen with least PAPR above all communication antennas. The proposed PAPR reduction approach is applied independently on each transmitted antenna, and so the PAPR can be extremely reduced. Moreover, the OGWO optimization based PAPR reduction technique will provide better performance and it was been promoted as an uncomplicated way for PAPR reduction. The proposed approach will be analyzed with various novel PAPR reduction schemes to show the effectiveness.

scholarly journals INTER CARRIER INTERFERENCE AND SIGNAL TO INTERFERENCE RATIO OF VARIOUS PULSE SHAPING FUNCTIONS USED IN OFDM SYSTEM WITH CARRIER FREQUENCY OFFSET

2012 ◽  
pp. 68-71
Author(s):  
SHANKAR AENAGANDULA ◽  
ASHOK KUMAR ◽  
SRINIVAS K ◽  
MONIKA NANDA
Keyword(s):  
Carrier Frequency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Pulse Shaping ◽  
Carrier Frequency Offset ◽  
Signal To Noise Ratio ◽  
Frequency Offset ◽  
Performance Comparison ◽  
Intercarrier Interference ◽  
Ofdm Systems ◽  
Ofdm System

Orthogonal Frequency Division Multiplexing (OFDM) is the important modulation of choice for fourthgeneration broadband multimedia wireless systems. This paper is focused on the problem of reducing the intercarrierinterference (ICI) and signal to noise ratio in the transmission over OFDM using various pulse shaping methods. Here we have performed a detailed performance comparison of various pulse shaping functions used in OFDM System with Carrier Frequency Offset. They appear to be suitable for transmission in OFDM systems with carrier frequency offset. The results obtained by analysis show that the performance improvement over conventional pulse shapes, are significant for reducing average intercarrier-interference (ICI) power and increased ratio of average signal power to average ICI power (SIR).

scholarly journals Comparison of SPS and FA methods for Blind Carrier Frequency Offset Estimation in OFDM systems

2022 ◽  
Vol 16 ◽  
pp. 7-11
Author(s):  
K. Seshadri Sastry ◽  
K. Baburao ◽  
A.V. Prabu ◽  
G.Naveen Kumar
Keyword(s):  
Carrier Frequency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Carrier Frequency Offset ◽  
Frequency Offset ◽  
Intercarrier Interference ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Frequency Offset Estimation ◽  
Synchronization Errors ◽  
Carrier Frequency Offset Estimation

In orthogonal frequency-division multiplexing (OFDM) systems, synchronization issues are of great importance since synchronization errors might destroy the orthogonality among all subcarriers and, therefore, introduce intercarrier interference (ICI) and intersymbol interference (ISI). Several schemes of frequency offset estimation in OFDM systems have been investigated. This paper compares performance and computational complexity of Smoothing Power Spectrum (SPS) and Frequency Analysis (FA) methods for blind carrier frequency offset (CFO) estimation in OFDM systems.

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