A Data Aided Estimation Algorithm of Decimal Frequency Offset for OFDM System

2014 ◽  
Vol 902 ◽  
pp. 385-391
Author(s):  
Yun Tang ◽  
Feng Zheng ◽  
Hang Liu ◽  
Tian Qi Miao
Keyword(s):  
Spectral Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Estimation Algorithm ◽  
Frequency Offset ◽  
Frequency Division ◽  
Ofdm System ◽  
Mechanism Of Formation ◽  
High Spectral Efficiency ◽  
Simulation Results ◽  
Better Than

In recent years, orthogonal frequency division multiplexing (OFDM) technology has drawn widespread attention for its high spectral efficiency, and has doing better on combating multipath interference than traditional technology.The reason why OFDM system has high spectral efficiency is that it takes advantage of the orthogonality between sub-carriers,characteristic of which can eliminate interference of each subcarrier even when the spectrum of them overlapped.It is the demanding of orthogonality between subcarriers to demodulate signals that makes OFDM system extremely sensitive to frequency offset. Even a little frequency offset can bring inter-carrier interference.This paper studied the mechanism of formation of interference among sub-carriers, and proposed a frequency offset estimation algorithm by changing the structure of data symbols so that the data symbols can act as training sequence.The simulation results show that the proposed algorithm performs better than S.C algorithm in many aspects, such as MSE, BER, Constellation and so on.

An Iterative Frequency Offset Estimation Algorithm for OFDM System

2013 ◽  
Vol 765-767 ◽  
pp. 2858-2861
Author(s):  
Feng Zheng ◽  
Yun Tang ◽  
Hang Liu
Keyword(s):  
Data Structure ◽  
Wireless Communications ◽  
Iterative Algorithm ◽  
Orthogonal Frequency Division Multiplexing ◽  
Estimation Algorithm ◽  
Frequency Offset ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Frequency Offset Estimation ◽  
Ofdm System

Orthogonal Frequency Division Multiplexing (OFDM) is considered as an important technique for future wireless communications. In addition, OFDM has a better performance at inter symbol interference (ISI). One of the major disadvantages of the multi-carrier modulation is about the sensitivity of the performance to a frequency offset. In this paper, we propose an iterative algorithm of frequency offset estimation for the OFDM system. The fundamental algorithm of our iterative algorithm is the frequency pilot aided algorithm. When we get a result with the fundamental algorithm every time, we use the result to estimate for a second time. The algorithm we proposed does not require some additional pilots or changing the data structure of the fundamental algorithm.

scholarly journals Spectral Efficiency of FBMC Over OFDM System

2019 ◽  
Vol 9 (2S3) ◽  
pp. 235-237
Keyword(s):  
Spectral Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Filter Bank ◽  
Average Power ◽  
Primary Objective ◽  
Mobile Environments ◽  
Frequency Division ◽  
Doppler Shifts ◽  
Wireless Broadband ◽  
High Spectral Efficiency

Significant wireless broadband technology used in various cellular standards is Orthogonal Frequency Division Multiplexing (OFDM) which will make use of Multi Carrier Modulated (MCM) systems. Even though OFDM has numerous advantages, it is hard to employ OFDM for complex networks. It is very hard to establish synchronization in mobile environments as it is difficult to predict the Doppler shifts of different users, which results in inter carrier interference (ICI). Further, filters associated with OFDM carrier have comparatively large sidebands which outcomes in Out of Band (OOB) radiations. Insufficient spectral usage is provided by CP-OFDM by using more guard band. So the problems caused by traditional OFDM/CP-OFDM can be answered by employing a new system termed as Filter Bank Multi Carrier (FBMC) System. It is a form of MCM and it can be considered as an advanced cyclic-prefix (CP-OFDM). In OFDM, whole band gets filtered while in FBMC, each sub carrier band is independently filtered. The primary objective of this work is to relate the performance of 5G modulation technique such as FBMC against OFDM and to suggest an ideal waveform for 5G communication in regard to high spectral efficiency, spectral density, BER and less Peak to Average Power Ratio (PAPR).

scholarly journals A CCM-Based OFDM System with Low PAPR for Sparse Source

2018 ◽  
Vol 2018 ◽  
pp. 1-7
Author(s):  
Qinbiao Yang ◽  
Zulin Wang ◽  
Qin Huang
Keyword(s):  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Coded Modulation ◽  
High Peak ◽  
Frequency Division Multiplexing ◽  
Power Ratio ◽  
Frequency Division ◽  
Ofdm System ◽  
Simulation Results ◽  
Clipping And Filtering

Orthogonal frequency division multiplexing (OFDM) usually suffers high peak-to-average power ratio (PAPR). As shown in this paper, PAPR becomes even severe for sparse source due to many identical nonzero frequency OFDM symbols. Thus, this paper introduces compressive coded modulation (CCM) in order to restrain PAPR by reducing identical nonzero frequency symbols for sparse source. As a result, the proposed CCM-based OFDM system, together with iterative clipping and filtering, can efficiently restrain the high PAPR for sparse source. Simulation results show that it outperforms about 4 dB over the traditional OFDM system when source sparsity is 0.1.

Channel Estimation Based on Interpolation in OFDM System

2010 ◽  
Vol 439-440 ◽  
pp. 794-798
Author(s):  
Yue Hua Cui ◽  
Shuang Ye ◽  
Qiu Rui Wu ◽  
Jian Hua Liu ◽  
Yan Dai
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Estimation Algorithm ◽  
Linear Interpolation ◽  
High Rate ◽  
Transform Domain ◽  
Rate Data ◽  
Ofdm System ◽  
High Spectral Efficiency ◽  
Low Pass

OFDM（Orthogonal Frequency Division Multiplexing）is a new modulation technology, which can reduce multi-pass interference efficiently. It splits a high-rate data stream into a number of lower-rate data streams which can be transmitted simultaneously over a number of subcarriers. It brings high spectral efficiency. In this paper, we first introduce the channel estimation algorithm based on comb-pilot in OFDM system, and emphasis on analysis and comparison of the three kinds of interpolation methods: linear interpolation, low-pass interpolation and transform-domain interpolation. We use MATLAB to carry out the system simulation, and its results indicate that: The performance of low-pass interpolation is the best ,but it’s hard to carry out; transform-domain interpolation’s performance and complexity are both between above two methods.

The Study of Interpolation Algorithms in OFDM Systems

2013 ◽  
Vol 321-324 ◽  
pp. 2837-2840
Author(s):  
Xi Jun Zhang ◽  
Jian Bin Xue ◽  
Ying Lin ◽  
Ji Ai He
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm Systems ◽  
Ofdm System ◽  
Simulation Process ◽  
Interpolation Algorithms ◽  
Simulation Results

Orthogonal frequency division multiplexing (OFDM) is a kind of highly transmission technology. It has been taken more and more attention in many ways. In this paper it mainly discussed the simulation process and several interpolation algorithms in OFDM system. Using computer we simulate the interpolation algorithms in OFDM channel estimation. Through the simulation results we compare the advantage and disadvantage of the interpolation algorithms. At last we can use the conclusion to choose the correct interpolation algorithms in OFDM channel estimation.

An Improved Algorithm Based on Optimized PTS in MIMO-OFDM System

2013 ◽  
Vol 765-767 ◽  
pp. 2801-2804
Author(s):  
Ya Jing Wang ◽  
Ya Zhen Li ◽  
Li Qun Huang
Keyword(s):  
Spectral Efficiency ◽  
Communication System ◽  
High Speed ◽  
Fourth Generation ◽  
Ofdm System ◽  
Broadband Wireless ◽  
High Spectral Efficiency ◽  
Mimo Ofdm ◽  
Simulation Results ◽  
Improved Algorithm

The fourth generation mobile communication system is a high-speed broadband wireless communication system, it needs MIMO and OFDM technology which have high spectral efficiency and suitable for a multi-path fading channel. Because the MIMO-OFDM system is still an multi-carrier modulation system, the main drawback is the high PAPR value. This paper proposed an improved algorithm based on optimized PTS to reduce PAPR in STBC MIMO-OFDM system. The simulation results show that the improved algorithm can effectively reduce the PAPR value and do not increase the amount of computation in STBC MIMO-OFDM system.

scholarly journals Improved Interference Cancelation Channel Estimation Method in OFDM/OQAM System

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Shangfei Qiu ◽  
Lunsheng Xue ◽  
Peng Wu
Keyword(s):  
Channel Estimation ◽  
Spectral Efficiency ◽  
Orthogonal Frequency Division Multiplexing ◽  
Estimation Method ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Estimation Performance ◽  
Interference Cancelation ◽  
Simulation Results ◽  
Method Show

To the significant amount of pilot overhead of the interference cancelation methods in orthogonal frequency division multiplexing (OFDM) based on offset quadrature amplitude modulation (OFDM/OQAM) system, we proposed an improved interference cancelation method (ICM) for OFDM/OQAM system in this paper. In this method, we use the auxiliary pilot (AP) to eliminate the influence of the intersymbol interference on channel estimation, which can reduce the pilot overhead of OFDM/OQAM system significantly. At the same time, to improve the channel estimation performance, we analyze the source of the intrinsic interference of system and its distribution in time and frequency domain, then, we reset the interference cancelation range of AP, which can cancel more intrinsic interference for OFDM/OQAM system. According to the results of performance analysis, compared to the conventional interference cancelation methods, the proposed method performs better in terms of energy efficiency and spectral efficiency. Also, the simulation results of the proposed method show that the proposed method can outperform traditional interference cancelation methods in channel estimation performance.

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