scholarly journals Channel Estimation for OFDM-Based Amplify-and-Forward Cooperative System Using Relay-Superimposed Pilots

2018 ◽  
Vol 2018 ◽  
pp. 1-6
Author(s):  
Xianwen He ◽  
Gaoqi Dou ◽  
Jun Gao
Keyword(s):  
Lower Bound ◽  
Channel Estimation ◽  
Data Stream ◽  
Direct Link ◽  
Frequency Division ◽  
Cooperative System ◽  
Amplify And Forward ◽  
System A ◽  
Pilot Symbols ◽  
Simulation Results

For the OFDM-based Amplify-and-Forward cooperative system, a novel relay-superimposed pilot strategy is proposed, where the source pilot symbols are frequency division multiplexed to estimate the cascaded channel while relay pilot sequence is superimposed onto the top of the cooperative data stream for second-hop channel estimation. This method avoids the loss of data rate for additional pilot subcarriers but results in the interference of unknown cooperative data. To remove the interference of cooperative data during the estimation of second-hop channel, the Cooperative Interference Cancelation scheme assisted by cooperative data from direct link is proposed. We derive the approximated lower bound for the MSE of second-hop channel estimation. Simulation results are presented to validate the performance of the proposed schemes.

scholarly journals Improved Training Sequence Channel Estimation Scheme in 16QAM MB-OFDM UWBoF System

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Changqing Xiang ◽  
Xi Yang ◽  
Xuan Zhou ◽  
Xiaojun Zhu ◽  
Jincan Xu ◽  
...  
Keyword(s):  
Channel Estimation ◽  
Time Domain ◽  
Orthogonal Frequency Division Multiplexing ◽  
Single Mode ◽  
Training Sequence ◽  
Single Mode Fiber ◽  
Frequency Division ◽  
Training Sequences ◽  
Estimation Scheme ◽  
Simulation Results

In this paper, an improved channel estimation scheme based on time-domain orthogonal gray complementary training sequence (Golay TS) is proposed to resist subcarrier mutual beat interference in 16-quadrature amplitude modulation multiband orthogonal-frequency-division-multiplexing ultrawide band over fiber (16QAM MB-OFDM UWBoF) systems. The simulation results showed that the performance of system with the improved Golay TS channel estimation scheme was improved by about 1 dB compared with the traditional Golay TS channel estimation scheme, at a bit error rate (BER) of 3.8 × 10−3 after 70 km standard single mode fiber (SSMF) transmission. At the same time, the synchronization and channel estimation performance of Golay TS and the selected frequency-domain orthogonal training sequences (TSs) were compared. The simulation results showed that the performance of system with the TSs channel estimation was improved by about 2.7 dB compared with the improved Golay TS channel estimation.

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.

scholarly journals Training Based Channel Estimation for Multitaper GFDM System

2017 ◽  
Vol 2017 ◽  
pp. 1-8
Author(s):  
Shravan Kumar Bandari ◽  
Venkata Mani Vakamulla ◽  
A. Drosopoulos
Keyword(s):  
Channel Estimation ◽  
Pulse Shaping ◽  
Minimum Mean Square Error ◽  
Computational Cost ◽  
Estimation Methods ◽  
Frequency Division ◽  
Prolate Spheroidal ◽  
Prototype Filter ◽  
Key Features ◽  
Simulation Results

Recent activities in the cellular network world clearly show the need to design new physical layer waveforms in order to meet future wireless requirements. Generalized Frequency Division Multiplexing (GFDM) is one of the leading candidates for 5G and one of its key features is the usage of circular pulse shaping of subcarriers to remove prototype filter transients. Due to the nonorthogonal nature of the conventional GFDM system, inherent interference will affect adversely channel estimation. With Discrete Prolate Spheroidal Sequences (DPSSs) or multitapers as prototype filters an improved orthogonal GFDM system can be developed. In this work, we investigate channel estimation methods for multitaper GFDM (MGFDM) systems with and without Discrete Fourier Transform (DFT). The simulation results are presented using Least Squares (LS) and Minimum Mean Square Error (MMSE) channel estimation (CE) methods. DFT based CE methods provide better estimates of the channel but with an additional computational cost.

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.

A Beamforming Pilots Scheme for Massive MIMO System

2014 ◽  
Vol 568-570 ◽  
pp. 1259-1262
Author(s):  
Hong Zhang ◽  
Dong Lai Hao ◽  
Xiang Yang Liu
Keyword(s):  
Channel Estimation ◽  
Massive Mimo ◽  
Mimo System ◽  
Channel State ◽  
State Information ◽  
Downlink Beamforming ◽  
System A ◽  
Efficiency Performance ◽  
Simulation Results ◽  
Better Than

To acquire channel state information for Massive MIMO system , a downlink beamforming pilots scheme is proposed for efficient channel estimation. The channel estimation overhead of the proposed scheme is independent on the BS antenna numbers, and is only proportional to user numbers. MMSE precoding method is derived to implement the proposed scheme. Finally in simulation the proposed algorithm is compared with conventional algorithms without beaforming training in spectral efficiency performance. The simulation results show that the proposed scheme performs better than the existing schemes.

Research on Uplink Channel Estimation Method in TD-LTE System

2011 ◽  
Vol 135-136 ◽  
pp. 847-851
Author(s):  
Cui Zhen Sun ◽  
Zhao Hua Zeng
Keyword(s):  
Channel Estimation ◽  
Estimation Method ◽  
Data Rate ◽  
Pilot Signal ◽  
High Data ◽  
System A ◽  
Term Evolution ◽  
Simulation Results ◽  
Evolution Scheme

LTE is a long term evolution scheme of 3GPP, as a using extensively communication standards, it has higher data rate and higher quality. Channel estimation plays a quite important role in the LTE system which requires the high data rate and quality. In the article, based on the analysis of the LS and MMSE algorithms of the LTE system, a advised algorithm is adopted. The pilot signal is processed before the channel estimation by reducing noise in time domain. The simulation results demonstrate that the advised algorithm is a preferable choice in estimation performance, simultaneously; the advised has obviously reduced the algorithm complexity.

Sign in / Sign up

Export Citation Format

Share Document