Performances of OFDM‐CDMA receivers with MIMO communications

This paper proposes a new adaptive iterative method to impulsive noise mitigation in OFDM systems over in-home power line channels. The performance of impulsive noise mitigation methods based on OFDM decreases when the impulsive noise energy is higher than a certain threshold. To compensate for the limitations of these systems and to be able to adopt it for all sub-carriers, here, the 64-QAM constellation is applied together with Alamouti space time coding to transmit, MIMO In-home power line channel and zero-forcing estimate (ZFE) with continuous loop impulsive noise detection and mitigation together with maximum-likelihood detection (MLD) are adopted to receive. At the receiver, after ZFE, impulsive noise detection algorithm based on adaptive threshold for estimating the impulsive noise, determines the locations and amplitudes of the impulsive noises. The effect of impulsive noise on the noise symbols using the mask based on the soft decision method is reduced. Later, using MLD, the original signal is estimated. The algorithm is simulated and analyzed, and its performance is compared to other methods. The results show the superiority and robustness of the proposed method.

Section: The Proposed Methodsmentioning

confidence: 99%

Section: The Proposed Methodsmentioning

confidence: 99%

Impulsive noise estimation and suppression in OFDM systems over in‐home power line channels

Ahadiat

Azmi

Haghbin

2014

“…Because the channel matrix is known, the filter (zero-forcing) [28] for the kth transmitted vector is given by…”

Section: Sic-jga Algorithm For Mimo Detectionmentioning

confidence: 99%

New detection algorithms based on the jointly Gaussian approach and successive interference cancelation for iterative MIMO systems

Zhong

Zhao

et al. 2012

SUMMARYA new detection algorithm based on the jointly Gaussian approach (JGA) and successive interference cancelation (SIC), named the SIC-JGA algorithm, is proposed for iterative MIMO systems. Both the a priori symbol estimates of the undetected layers and the a posteriori symbol estimates of the previously detected layers are used in the SIC process. To reduce the complexity of covariance matrix inversion in the proposed algorithm, simplified algorithms named S-SIC-JGA are investigated for both the single path and multipath block fading channels under M Phase Shift Keying modulations. A detailed complexity analysis is presented for both the SIC-JGA and S-SIC-JGA algorithms. Numerical results exhibit that the system using the SIC-JGA algorithm outperforms the JGA algorithm, with an additional complexity for determining the detection order of SIC. The S-SIC-JGA algorithm has a much lower complexity compared with the SIC-JGA algorithm while experiencing an acceptable system performance degradation. Proper detection algorithms can be chosen in different iterations to balance the system performance and the detection complexity.

“…It has been demonstrated in [14] that the relay antenna selection is an effective method to resolve this problem. The traditional antenna selection schemes [15][16][17][18] cannot be directly adopted because they do not consider the precoding operation at UEs. A joint antenna selection and zero-forcing spatial multiplexing scheme for MIMO-PNC was proposed in [19,20], while it cannot be used to resolve the antenna selection problem of SSA-NC because of the different signal alignment method.…”

Section: Introductionmentioning

confidence: 99%

Joint relay antenna and precoding selection for K‐user MIMO Y channels with physical‐layer network coding

Wang

Song

Ning

et al. 2015

SUMMARYIn this paper, we focus on physical-layer network coding (PNC) used in multiple-input multiple-output (MIMO) Y channels, where K users simultaneously exchange messages with each other via a shared relay. For MIMO-PNC, signal space alignment for network coding (SSA-NC) is a promising precoding method and can achieve K(K-1) degrees of freedom if certain conditions can be satisfied. An important one is that the number of relay antennas is less than twice of the user antennas, that is, the dimensionality constraint of SSA-NC. In this paper, we focus on a particular scenario where the dimensionality constraint is not satisfied. In order to resolve this problem, we develop a scheme of jointly selecting relay antennas and precoding vectors. In particular, a novel precoding and detection method is presented to alleviate the interference caused by simultaneous transmissions. Through analyzing the symbol error rate performance of MIMO-PNC, we establish the relationship between the achievable flow diversity gain and the optimal number of the antennas, and a precoding selection method is designed under a given relay antenna configuration. Finally, we propose a joint scheme to select the optimal relay antenna configuration and precoding vectors. Numerical results demonstrate that the presented scheme can effectively support MIMO-PNC in various scenarios.