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The scaling up of antennae and terminals in large-scale multiple-input multiple-output (MIMO) systems helps increase the spectral efficiency at the penalty of prohibitive computational complexity. In conventional linear detection such as the minimum mean square error (MMSE) signal detection, the high complexity is mainly caused by solving the inversion of random matrix, especially in large-scale MIMO...
An improved MMSE method aimed to reduce the computational burden is proposed in this paper. In the method, the covariance matrix inversion is approximated by the expansion of N-order polynomials of weighted Kapteyn series which has low truncation errors. In this method, an unconstrained non-linear optimization model is established and an iterative algorithm based on coordinate rotation is used to...
In this paper, we investigate the impact of the carrier-sensing range on the link performance in a dense wireless network. Considering small-scale fading effects, we fix the carrier-sensing threshold and adaptively adjust the carrier-sensing range. At first, we assume a close transmitter-receiver distance and model the network nodes as a homogeneous Poisson point process (PPP). Then we obtain the...
This paper proposed a robust spatial spectrum sensing algorithm to apply to a communication scenario which exist the estimated error of noise power and the jamming. A modified approximate model is proposed to include the estimated error of noise power and the jamming. The corresponding performance indicators are proposed. The proposed robust algorithm estimates the estimated error vector of noise...
Regular zero-forcing (RZF) precoding algorithm is well- known as its low complexity and high performance in massive MIMO systems. However, when the number of transmitting antennas increases, the matrix inversion in RZF leads to high algorithmic complexity. In this paper, we propose an improved Newton iteration to estimate the matrix inversion in RZF precoding. Compared with the traditional Newton...
In order to reduce the computational complexity of precoding in massive MIMO systems, we propose a Kapteyn-series based regularized zero-forcing (RZF) approach to approximate the matrix inversion. Numerical results show that, when signal to noise ratio (SNR) is low or the error of channel estimation is large, the series-expansion based RZF precoding performs the same as ordinary RZF approach, and...
In this paper, one centralized resource allocation algorithm is proposed to minimize energy consumption in software defined wireless sensor networks (SD-WSNs). The energy consumption problem is formulated as an optimization problem, given quality-of-service (QoS) constraint defined as Signal-to-Interference-plus-Noise Ratio (SINR). Then, the nonconvex optimization problem is relaxed into a semidefinite...
Ultra-wide bandwidth (UWB) and Inertial Navigation (IN) have been adopted in high precision localization and tracking systems. However, the ranging measurements influenced by non-line-of-sight (NLOS) path may degrade the localization accuracy. Besides, inertial measurement errors are within the sensing data and constantly accumulate over the time. To overcome the above problems, we investigate NLOS...
In order to ensure the bit error rate and reduce the complexity simultaneously, in this paper, we propose a quasi-orthogonal space-time block code (QO-STBC) decoding algorithm based on pairwise-minimum mean square error (pairwise-MMSE). The complexity of the proposed algorithm has nearly linear complexity, lower than that of the pairwise algorithm. Meanwhile, the bit error rate of the proposed algorithm...
The distributed space-time code based on algebra theory in cooperative systems discussed in this paper is linear, but it doesn't satisfy the design criterion of orthogonal and quasi orthogonal space-time code. First the collaborative channel model is established and then we design the distributed space-time block codes which base in the model of two transmitting antennas and two receiving antennas...
In this paper we introduce a new kind of space time block code based on quaternion quasi-orthogonal design. The new code can transmitted through dual-polarized antennas and received through dual-polarized antennas. Compared with quasi-orthogonal space-time block codes, the new code can reduce bit error rate.
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