scholarly journals A Comprehensive Review on Channel Estimation Techniques in MIMO-OFDM

2019 ◽  
Vol 5 (5) ◽  
pp. 6
Author(s):  
Ritu Babulkar
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Mimo Channel ◽  
Noisy Channel ◽  
Frequency Division ◽  
Available Bandwidth ◽  
Estimation Techniques ◽  
Transmission Technique ◽  
Mimo Ofdm ◽  
Transmitting Antenna

In wireless communication, more than one signals are transmitted in the channel by using the concept of Orthogonal frequency division multiplexing (OFDM) which efficiently handles the inter symbol interference and utilizes the frequency and available bandwidth efficiently. Whereas for OFDM transmission technique is integrated with MIMO channel which contains multiple transmitter and receiver antenna at both ends. By using MIMO-OFDM system, different signals can be transmitted at the same time by utilizing same frequency and get separated in the space.  As the transmitting antenna transmit signal in the noisy channel so, it is required to estimate the noise in the channel. The channel estimation technique in noisy channel helps in analyzing the effect of noise on the transmitted data. In this paper, a brief review is presented for channel estimation techniques for MIMO-OFDM.

A New Method for MIMO-OFDM Channel Estimation Based on Discrete Wavelet Transform

2012 ◽  
Vol 182-183 ◽  
pp. 2066-2070
Author(s):  
Hui Shi ◽  
Ren Wang Song ◽  
Gang Fei Wang
Keyword(s):  
Wavelet Transform ◽  
Channel Estimation ◽  
Discrete Wavelet Transform ◽  
Orthogonal Frequency Division Multiplexing ◽  
Multiple Input Multiple Output ◽  
Mimo Channel ◽  
Discrete Wavelet ◽  
Input Multiple Output ◽  
Estimation Scheme ◽  
Mimo Ofdm

This paper puts forward a suitable channel estimation scheme for multiple input multiple output and orthogonal frequency division multiplexing system (MIMO-OFDM) based on discrete wavelet transform. According to the least-squares standard (LS), this plan uses pilot to estimate the unit impulse response of MIMO channel firstly, then does wavelet denoising in changing domain, in order to reduce the frequency spectrum leakage and improve the estimation precision. At the same time, this method does not need to know channel information in advance, and can follow up the changes of channel on time with good error rate performance.

scholarly journals Pilot Sequence Assisted Channel Estimation in MIMO/SIMO/SISO-OFDM Systems

2020 ◽  
Author(s):  
Xiao Zhou ◽  
Chengyou Wang ◽  
Qun Wu
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Estimation Method ◽  
High Order ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System ◽  
Input Multiple Output ◽  
Mimo Ofdm ◽  
Single Input

Abstract For improving the communication system performance in multiple input multiple output- orthogonal frequency division multiplexing (MIMO-OFDM) system, single input multiple output-orthogonal frequency division multiplexing (SIMO-OFDM) system, single input single output-orthogonal frequency division multiplexing (SISO-OFDM) system, this paper introduces a pilot assisted channel estimation method. The proposed method is a combination of pilots and channel estimation based on known channel state information (CSI). First, the pilots are used to maintain the orthogonality characteristics of space time block coding (STBC). By designing the interference-free pilots we estimating the channel, and then with the pre-estimated channel characteristics data is decoded at the MIMO-OFDM system receiver. In this paper, we proposed four kinds of comb-type pilot sequences with interference-free pilots designing among consecutive subcarriers. The proposed pilot assisted channel estimation method in MIMO/SIMO/SISO-OFDM systems could be well adopted with different low and high order modulations. This flexible transmission mechanism can save pilot overhead and has strong anti-interference ability in dynamic channels. Moreover, high-order constellation modulation level will enhance the channel capacity in MIMO/SIMO/SISO-OFDM system. Therefore, it can be used as a candidate technology for 5G or 6G MIMO/SIMO/SISO-OFDM system.

scholarly journals Efficacy of Channel Estimation and Efficient use of Spectrum using Optimised Cyclic Prefix (CP) in MIMO-OFDM

2019 ◽  
Vol 9 (2) ◽  
pp. 3032-3038
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Average Power ◽  
Cyclic Prefix ◽  
Spectrum Efficiency ◽  
Frequency Division ◽  
Flower Pollination ◽  
Mimo Ofdm ◽  
Analysis Of Results ◽  
Optimization Methodology

The performance of MIMO-OFDM network gets affected due to problems in the channel estimation which is essential for designing receivers. The issues in MIMO are due to sizable inadequate Cyclic Prefix (CP) in admired Orthogonal frequency division multiplexing (OFDM), a massive amount of detection error and channel estimation problem occurs due to which performance delay turn out. This paper proposes a solution, its implementation and analysis of results. The article uses the BAT and Modified Flower Pollination (MFP) algorithm for optimizing the CP length. Minimum CP length gets considered to achieve better throughput for the same MFP algorithm. This algorithm has been proposed to optimize CP length to achieve minimum error rate of bit (BER) and PAPR-Peak to average power ratio, thereby maximizing the spectrum efficiency. For comparing the efficacy of optimized CP and unoptimized CP, the paper examines the results obtained on studying the performance in the spectrum. The performance of BAT and MFP algorithm are compared with each other to determine the better optimization methodology for the problem.

Improving Space-Time-Frequency MIMO-OFDM with ICI Self-Cancellation Scheme using Least Square Error Estimator

2015 ◽  
Vol 12 (1) ◽  
pp. 25
Author(s):  
Nur Farahiah Ibrahim ◽  
Zahari Abu Bakar ◽  
Azlina Idris
Keyword(s):  
Channel Estimation ◽  
Orthogonal Frequency Division Multiplexing ◽  
Symbol Error Rate ◽  
Space Time ◽  
Least Square ◽  
Error Estimator ◽  
Frequency Diversity ◽  
Time Frequency ◽  
Mimo Ofdm ◽  
Subcarrier Mapping

Channel estimation techniques for Multiple-input Multiple-output Orthogonal Frequency Division Multiplexing (MIMO-OFDM) based on comb type pilot arrangement with least-square error (LSE) estimator was investigated with space-time-frequency (STF) diversity implementation. The frequency offset in OFDM effected its performance. This was mitigated with the implementation of the presented inter-carrier interference self-cancellation (ICI-SC) techniques and different space-time subcarrier mapping. STF block coding in the system exploits the spatial, temporal and frequency diversity to improve performance. Estimated channel was fed into a decoder which combined the STF decoding together with the estimated channel coefficients using LSE estimator for equalization. The performance of the system was compared by measuring the symbol error rate with a PSK-16 and PSK-32. The results show that subcarrier mapping together with ICI-SC were able to increase the system performance. Introduction of channel estimation was also able to estimate the channel coefficient at only 5dB difference with a perfectly known channel.

scholarly journals Channel estimation of OFDM in C-band communication systems under different distribution conditions

2021 ◽  
Vol 23 (3) ◽  
pp. 1778
Author(s):  
Heba Abdul-Jaleel Al-Asady ◽  
Hassan Falah Fakhruldeen ◽  
Mustafa Qahtan Alsudani
Keyword(s):  
Fourier Transform ◽  
Channel Estimation ◽  
Fast Fourier Transform ◽  
Communication Systems ◽  
Orthogonal Frequency Division Multiplexing ◽  
Frequency Division Multiplexing ◽  
Frequency Division ◽  
Ofdm System ◽  
High Data ◽  
High Efficient

<p>Orthogonal frequency division multiplexing (OFDM) is a transmission system that uses multiple orthogonal carriers that are sent out at the same time. OFDM is a technique for mobile and wireless communication that has high-efficient frequency utilization, high data-rate transmission, simple and efficient implementation using the fast Fourier transform (FFT) and the inverse fast Fourier transform (IFFT), and reduces inter symbol interference (ISI) by inserting cyclic prefix (CP). One of the most important approaches in an OFDM system is channel estimation. In this paper, the orthogonal frequency division multiplexing system with the Rayleigh channel module is analyzed for different areas. The proposed approach used large numbers of subcarriers to transmit the signals over 64-QAM modulation with pilot add channel estimation. The accuracy of the OFDM system is shown in the measuring of the relationships of peak power to the noise ratio and bit error rate.</p>

scholarly journals A Comprehensive Review on Channel Estimation in OFDM System

2019 ◽  
Vol 5 (3) ◽  
pp. 6 ◽  
Author(s):  
Neha Dubey ◽  
Ankit Pandit
Keyword(s):  
Channel Estimation ◽  
Mean Square Error ◽  
Orthogonal Frequency Division Multiplexing ◽  
Transmission Rate ◽  
Minimum Mean Square Error ◽  
Estimation Method ◽  
Least Square ◽  
Estimation Methods ◽  
Mean Square ◽  
Mimo Ofdm

In wireless communication, orthogonal frequency division multiplexing (OFDM) plays a major role because of its high transmission rate. Channel estimation and tracking have many different techniques available in OFDM systems. Among them, the most important techniques are least square (LS) and minimum mean square error (MMSE). In least square channel estimation method, the process is simple but the major drawback is it has very high mean square error. Whereas, the performance of MMSE is superior to LS in low SNR, its main problem is it has high computational complexity. If the error is reduced to a very low value, then an exact signal will be received. In this paper an extensive review on different channel estimation methods used in MIMO-OFDM like pilot based, least square (LS) and minimum mean square error method (MMSE) and least minimum mean square error (LMMSE) methods and also other channel estimation methods used in MIMO-OFDM are discussed.

Sign in / Sign up

Export Citation Format

Share Document