Co-channel Interference Characteristics Research Articles

Coordinated User Scheduling Based on Hybrid CSI in Multi-User MIMO Relay System with Limited Feedback

This paper considers coordinated user scheduling in a multi-user two-hop multi-input multi-output relay system with limited feedback. The proposed scheme utilizes a quantized transmit correlation and channel quality information, enabling to achieve both interference mitigation and multi-user diversity (MUD) gain. To this end, we first investigate the effect of quantization error on the statistical characteristics of co-channel interference (CCI) cased by the relay. Then, the coordinated user-scheduling strategy is designed with the use of eigen-beamforming to maximize the desired signal power in an instantaneous manner while minimizing the CCI in an average sense. Analytic and numerical results show that the proposed scheme can maximize the achievable sum-rate by handling a tradeoff between interference mitigation and MUD gain according to the number of quantization bits, providing a large sum-rate performance in the presence of quantization error.

Effect of Imperfect Transmit Correlation on Statistical Beamforming in Multi-User Cellular Systems

This letter investigates the effect of imperfect transmit correlation on the performance of statistical beamforming in terms of average signal-to-interference plus noise ratio (SINR) in a correlated multi-user multi-antenna cellular system. The average SINR of the statistical beamforming depends on the accuracy of transmit correlation information as well as the characteristics of co-channel interference (CCI) from adjacent base stations. It is shown by means of multivariate Taylor series expansion that the average SINR degradation due to imperfect transmit correlation is associated with the mean squared error (MSE) and the number of quantization bits, and that those effect significantly varies depending on the correlation magnitude and the phase difference between the transmit correlation coefficient of the intended and CCI channel.

Pilot-Based Channel State Feedback in TDD/MIMO Systems with Co-channel Interference

This paper proposes a pilot-based channel state information (CSI) feedback from a terminal to a base station (BS), considering the terminal's co-channel interference in a time-division duplex/multi-input multi-output system. In the proposed method, the terminal determines a precoding matrix according to the terminal's co-channel interference characteristics and transmits the precoded pilot signals on uplink. Using the responses of the precoded pilot signals, the BS determines appropriate weight vectors for downlink transmit beams considering the terminal's interference characteristics. Furthermore, the BS can predict the terminal's output signal-to-interference-plus-noise power ratio (SINR) for the downlink data stream. Numerical results show that the BS can achieve efficient transmission and accurate SINR prediction using the proposed CSI feedback.

Adaptive cochannel interference suppression based on subarrays for HFSWR

The paper analyzes the characteristics of cochannel interference (CCI) in the high-frequency (HF) surface wave radar (HFSWR), which adopts the linear frequency modulated interrupted continuous wave (FMICW). CCI will influence all the range bins, including all the positive and negative frequencies, and the negative frequency range bins contain only the external interference information. Based on the above characteristics, we introduce a new adaptive coherent side-lobe cancellation (CSLC) algorithm based on subarrays that use the negative frequency range bin samples to estimate the interference covariance matrix and correlation vector. Experimental results confirm that the general and robust algorithm can achieve effective CCI suppression using the data recorded by the Ocean State Monitor and Analysis Radar (OSMAR2003, manufactured in 2003), located near Zhoushan in Zhejiang, China.

Target detection with high frequency surface wave radar in co-channel interference

OSMAR2003 high frequency surface ave radar (HFS R) system became operational i the autum of 2003. Apart from providing surveillance of over 40000 square kilometres of the sea environment such as surface current and sea state, the radar facility has the potential of detecting and tracking ships i all eather. Susceptibility of HFS R to external co-channel interference (CCI) may degrade performance significantly. I the paper, the characteristics of co-channel interference are described, and the authors present a comparative analysis of spatial domai and temporal domai interference mitigatio algorithms for target detection. Experimental results confirm that adaptive spatial domai interference suppressio using subarrays and temporal domai interference suppressio based o classical einer predictio filters are both helpful techniques for target detectio i a small-scale antenna array he the incident interference and the target signal have different incoming directions, but the spatial domai technique is likely to distort the angular response of the target signal simultaneously. Alternatively, he the incident interference and the backscattering target signal have the same incoming direction, the adaptive spatial domai algorithm ill simultaneously degrade the target signal hile providing effective interference mitigation, but the temporal domai technique ca ork ell o target detectio hile maintaining distortionless output of the target signal.