scholarly journals Cancellation Techniques for Co-channel Interference in MIMO-OFDM Systems and Evaluating Their Performance

2021 ◽  
Vol 5 (6) ◽  
pp. 824-839
Author(s):  
Varshini Rajesh ◽  
A. R. Abdul Rajak
Keyword(s):  
Fading Channels ◽  
Spread Spectrum ◽  
Interference Cancellation ◽  
Electromagnetic Waves ◽  
Wireless Systems ◽  
Rician Fading ◽  
Ofdm Systems ◽  
Channel Interference ◽  
Mimo Ofdm ◽  
New Generation

In a wireless communication system, the transmitted signal is exposed to various surfaces where it bounces and results in several delayed versions of the same signal at the receiver end. The delayed signals are in the form of electromagnetic waves that are diffracted and reflected from the various object surfaces. These result in co-channel interferences for wireless systems. MIMO has proven to be a striking solution for the new generation of wireless systems. MIMO-OFDM system with QPSK modulation is considered as the wireless system for studying the performance of interference cancellation techniques. The BER performance is studied in channels such as Rayleigh and Rician Fading Channels. The effects of interference are reduced to a certain extent by the inclusion of CDMA (spread spectrum technique) as Technique 1. The effects of interference on this system have been further reduced using the LMS filter as Technique 2. Hence, to show better performance in MIMO-OFDM systems, it is recommended to employ both CDMA and LMS filters to decrease the effects of co-channel interference. It is observed that the parameter BER reduces as the SNR increases for both these channels. Doi: 10.28991/esj-2021-01313 Full Text: PDF

Co-channel interference cancellation based on MIMO OFDM systems

2002 ◽  
Vol 9 (6) ◽  
pp. 8-17 ◽  
Author(s):  
L. Giangaspero ◽  
L. Agarossi ◽  
G. Paltenghi ◽  
S. Okamura ◽  
M. Okada ◽  
...  
Keyword(s):  
Interference Cancellation ◽  
Ofdm Systems ◽  
Channel Interference ◽  
Mimo Ofdm

scholarly journals A Novel Intercarrier Interference Cancellation for MIMO-OFDM Systems

1970 ◽  
Vol 9 (2) ◽  
pp. 120-130
Author(s):  
Aurupong Yiwleak ◽  
Chaiyod Pirak
Keyword(s):  
Fading Channels ◽  
Interference Cancellation ◽  
Frequency Offset ◽  
Complex Conjugate ◽  
Intercarrier Interference ◽  
Ofdm Systems ◽  
Mimo Ofdm ◽  
Space Frequency ◽  
Simulation Results ◽  
Ici Cancellation

The main impairment of an orthogonal frequency division multiplexing (OFDM) systems is an intercarrier interference (ICI) effect caused by a frequency offset. A zero-padded technique designed for a conjugate cancellation scheme in MIMO-OFDM systems for ICI cancellation is proposed by padding zero between two consecutive symbols over a space-frequency domain. At the receiver, the ICI cancellation and space-frequency diversity combining techniques are proposed. In this paper, a performance analysis is investigated and analyzed. In comparison with the conventional complex conjugate scheme, the outage probability expressions of the proposed system and the repetition-coded conjugate cancellation scheme are derived for quasi-static Rayleigh fading channels. Simulation results show the close agreement with those obtained by theoretical analysis, which could be used to estimate the proposed system performance. Finally, simulation results in time-varying frequency-selective fading channels, a bit error rate (BER) performance of the proposed system is significantly improved over both the ordinary zero-padded MIMO-OFDM systems and the repetition-coded conjugate cancellation scheme when the frequency offset is not greater than 10% of subcarrier spacing. Furthermore, the proposed system is shown to be able to attain significant diversity gain.

scholarly journals Simple Channel Estimation Techniques Based on Pilot-Assistance for STBC-Based MIMO-OFDM Systems

2009 ◽  
Author(s):  
Tran Duc Tan ◽  
Ta Duc Tuyen ◽  
Trinh Anh Vu ◽  
Huynh Huu Tue
Keyword(s):  
Channel Estimation ◽  
Fading Channels ◽  
Performance Improvement ◽  
Additive Noise ◽  
Multipath Fading ◽  
Ofdm Systems ◽  
Multipath Fading Channels ◽  
Pilot Assistance ◽  
Mimo Ofdm ◽  
High Flexibility

With equipping multiple antennas at both transmitter and receiver ends, the signals in the wireless OFDM systems could be transmitted over multipath fading channels for achieving benefits and high flexibility. In this paper, we focus on MIMO-OFDM systems that simultaneously perform channel estimation in order to combat additive noise, and multipath fading. The performance improvement is confirmed by simulations. Results show that the proposed MIMOOFDM scheme is quite robust in practical environments.

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