Channel Interference Suppression Research Articles

Analysis and compensation of frequency offset in co-site adjacent channel interference suppression

Due to the mismatch of the circuit oscillators, there will always be a frequency offset between the transmitter and the receiver. In the adjacent channel interference (ACI) suppression system using the reconstruction and cancellation method, the frequency offset decreases the accuracy of the reconstructed signal and introduces a time-varying term in the interference cancellation, resulting in poor performance of the ACI suppression. In this paper, the relationship between the normalized frequency offset, signal-to-noise ratio and the loss of interference suppression capability is analyzed through formula derivation and simulation. The validity of the frequency offset compensation method based on the pilot sequence is verified, and the relationship between the sequence length and the estimation accuracy is given. This paper provides necessary method reference and data support for the engineering of ACI suppression.

Adjacent channel interference suppression based on spectral extrapolation to enhance electromagnetic compatibility of co‐site radio devices

AbstractInterference suppression is an effective technique to enhance the electromagnetic compatibility of co‐site radio devices. In adjacent channel interference (ACI) suppression, a wideband analog‐to‐digital converter (ADC) is always required to sample the nonlinear characteristics of the interference signal to reconstruct the ACI, resulting in a significant increase in the cost of the receiver. To solve the problem, this article adopts spectral extrapolation in the ACI suppression. First, narrowband bandpass filter and ADC are employed to sample the in‐band component of the interference signal. Second the original wideband signal is recovered from the filtered signal by an inverse filter. Finally, the recovered signal is used for ACI reconstruction and cancellation. Simulation and experimental results show that when the adjacent channel leakage ratio is 45 dBc, the proposed method can achieve ACI suppression performance equivalent to that of the wideband ADC method. However, the required ADC sampling rate is only 1/3 of that of the wideband ADC.

Suppression Of Channel Interference In Optical Communication Networks Based On Blind Signal Separation

In order to overcome the problem of low accuracy and poor stability caused by the one-sided information blind separation analysis of the current communication channel interference suppression research methods, this paper proposes the optical communication network channel interference suppression method based on blind signal separation algorithm. The receiver unit, field programmable gate array (FPGA) unit, memory chip group and other modules are used to construct the channel signal acquisition system, and the collected signals are preprocessed by centralisation and whitening. Based on the signal preprocessing results, the blind separation of instantaneous linear mixed signals, blind separation of convolutional mixed signals and blind separation of sparse sources were comprehensively analysed to obtain the source signals and realise channel interference suppression of optical communication network. Experimental results show that this method has high interference precision, strong stability and good application prospect.

Suppression of channel interference in optical communication networks based on blind signal separation

In order to overcome the problem of low accuracy and poor stability caused by the one-sided information blind separation analysis of the current communication channel interference suppression research methods, this paper proposes the optical communication network channel interference suppression method based on blind signal separation algorithm. The receiver unit, field programmable gate array (FPGA) unit, memory chip group and other modules are used to construct the channel signal acquisition system, and the collected signals are preprocessed by centralisation and whitening. Based on the signal preprocessing results, the blind separation of instantaneous linear mixed signals, blind separation of convolutional mixed signals and blind separation of sparse sources were comprehensively analysed to obtain the source signals and realise channel interference suppression of optical communication network. Experimental results show that this method has high interference precision, strong stability and good application prospect.

On the implementation of adjacent channel interference suppression for direct digital six‐port receivers

AbstractIn this paper, practical approaches to implement the suppression of adjacent channel interference for direct digital six‐port receivers using compact integrated‐circuit dispersive delay lines are described and discussed in detail. Additional interference at the receiver output due to phase errors in the implementation is analyzed and calculated. Computer simulation results are provided, and further enhancement of the effectiveness of this suppression means is discussed. © 2002 John Wiley & Sons, Inc. Microwave Opt Technol Lett 32: 376–379, 2002.

New approaches to adjacent channel interference suppression in FDMA/TDMA mobile radio systems

The capacity and signal quality of wireless communication systems can be improved by enhancing receiver performance in the presence of adjacent channel interference (ACI), In this paper, maximum-likelihood sequence estimation (MLSE) receivers based on joint demodulation and successive cancellation of adjacent channel signals are developed. The proposed receivers provide significant improvement in performance over a wide range of carrier-to-interference ratios. To provide coherent reception, novel channel estimation techniques are used, exploiting knowledge of the transmit and receive filter responses. Performance is evaluated and compared via simulation for the Global System for Mobile communications (GSM) digital cellular system.