scholarly journals Theoretical Analysis of Interference Cancellation System Utilizing an Orthogonal Matched Filter and Adaptive Array Antenna for MANET

2019 ◽  
Vol 8 (3) ◽  
pp. 48 ◽  
Author(s):  
Harada ◽  
Takabayashi ◽  
Kobayashi ◽  
Sakakibara ◽  
Kohno
Keyword(s):  
Theoretical Analysis ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Mean Squared Error ◽  
Matched Filter ◽  
Array Antenna ◽  
Adaptive Array ◽  
Interference Signal ◽  
Minimum Mean Squared Error ◽  
Code Division Multiple

This study provides a mathematical model and theoretical analysis of an interference cancellation system combining an orthogonal matched filter (OMF) and adaptive array antenna that is called the extended OMF (EOMF). In recent years, an increase in the number of applications of mobile ad hoc networks (MANETs) is expected. To realize a highly reliable MANET, it is essential to introduce a method for cancelling the interference from other nodes. This research focuses on a scheme based on Code Division Multiple Access (CDMA) that enables simultaneous multiple access and low latency communication. However, there are problems with deteriorating performance due to the near–far problem and the increase in the amount of interference as the number of users increases. Additionally, another problem is that the spreading sequence of each user is unknown in a MANET. The OMF is expected to be a solution to these problems. The OMF performs interference cancellation by generating and subtracting a replica of the interference signal that is contained in the received signal. However, the OMF may generate an incorrect replica in the near–far problem. The EOMF compensates for the OMF’s weakness by combining the OMF with an adaptive array antenna. In this research, optimal parameters are derived from mathematical modelling and theoretical analysis of the EOMF. Specifically, the optimal weight vector and the minimum mean squared error that allow the adaptive algorithm to converge are derived and obtained from the numerical results.

scholarly journals A Blind Two-Stage Receiver for MIMO-CDMA Systems

2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
Fuh-Hsin Hwang ◽  
Tsui-Tsai Lin
Keyword(s):  
Multiple Access ◽  
Mean Squared Error ◽  
Multiple Input Multiple Output ◽  
Multiple Access Interference ◽  
Multipath Fading ◽  
Two Stage ◽  
Multipath Fading Channel ◽  
Minimum Mean Squared Error ◽  
Cdma Systems ◽  
Code Division Multiple

A blind two-stage multiple-input multiple-output (MIMO) receiver is proposed for code-division multiple access (CDMA) systems utilizing space-time block coding (STBC) over a multipath fading channel. Specifically, in the first stage, a signal-blocked (SB) interference-blocked (IB) detector is first constructed for collection of the desired signals and suppression of multiple access interference (MAI). In the second-stage, a decision-directed scheme is developed to alleviate desired signal cancellation. Computer simulations demonstrate that the proposed blind receiver can achieve a reliable output signal-to-interference-plus-noise ratio (SINR) performance approximating that of the optimal minimum mean squared error (MMSE) receiver and can exhibit the robustness against the finite data sample effect.

scholarly journals Analysis of Multiuser Detectors and Performance improvement in DS-CDMA system using Multistage Multiuser Detection Techniques

2021 ◽  
Author(s):  
Ravindrababu Jaladanki ◽  
Krishnarao Ede ◽  
Raja Rao Yasoda
Keyword(s):  
Computational Complexity ◽  
Multiuser Detection ◽  
System Performance ◽  
Interference Cancellation ◽  
Multiple Access ◽  
Signal Amplitude ◽  
Cdma System ◽  
Parallel Interference Cancellation ◽  
Detection Techniques ◽  
Code Division Multiple

Abstract Among the various interferences, the Multiple Access Interference (MAI) is a significant issue in Direct Sequence Code Division Multiple Access (DS-CDMA) system due to its users. When the number of users is increasing the MAI is likewise increments, subsequently the system performance progressively diminishes particularly in fading environment. In this paper, the system performance is improved by the proposed multistage multiuser detection technique called Multistage Multiuser Differencing Partial Parallel Interference Cancellation (DPPIC). This is the combination of Partial Parallel Interference Cancellation (PPIC) and Differencing Parallel Interference Cancellation (DPIC). Multistage Multiuser Parallel Interference Cancellation (PIC) and Multistage Multiuser PPIC techniques that exist gave improved system performance meaning as the number of stages increases the MAI decreases but at the cost of increased computational complexity. The computational complexity was reduced by utilizing Multistage Difference PIC (DPIC) technique but with no improvement in the performance. To improve the system performance as well as reduce the computational complexity Multistage Multiuser Partial Differencing Parallel Interference Cancellation (PDPIC) method can be used. The simulation results show that the proposed DPPIC technique performs better than PIC, PPIC and PDPIC in terms of Bit Error Rate (BER) versus normalized signal amplitude ( i.e., E b / N 0 ), but computational complexity slightly more than PDPIC in fading environment.

scholarly journals A proposed method for determination of weighted despreading sequences for a DS/CDMA system

2007 ◽  
Vol 3 (3) ◽  
Author(s):  
Younes Jabrane ◽  
Radouane Iqdour ◽  
Brahim Ait Es Said ◽  
Najib Naja
Keyword(s):  
Interference Cancellation ◽  
Fuzzy Systems ◽  
Code Division Multiple Access ◽  
Multiple Access ◽  
Additive White Gaussian Noise ◽  
Multiple Access Interference ◽  
Code Division Multiple ◽  
Parameter Values ◽  
Gaussian Noise Channels

The steeping chip weighting waveforms are used in multiple access interference cancellation by emphasizing the received spreading signal, therefore, that allows to solve the problem of orthogonality for the chip waveforms. Our paper presents a useful method based on fuzzy systems to determine the despreading sequences weighted by the steeping chip weighting waveforms for Direct Sequence Code Division Multiple Access DS/CDMA. The validity of our proposed method has been tested by numerical examples for an Additive White Gaussian Noise channels and shows that the parameter values of the chip weighting waveforms are good and the Bit Error Rate performance of the system does not undergone any degradation.

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