Performance of multiple-input multiple-output wireless communications systems using distributed antennas

In this contribution we propose and investigate a multiple-input multiple-output (MIMO) wireless communications system, where multiple receive antennas are distributed in the area covered by a cellular cell and connected with the base-station (BS). We first analyze the total received power by the BS through the distributed antennas, when assuming that the mobile's signal is transmitted over lognormal shadowed Rayleigh fading channels. Then, the outage probability of the distributed antenna MIMO systems is investigated, when considering various antenna distribution patterns. Furthermore, space-time coding at the mobile transmitter is considered for enhancing the outage performance of the distributed antenna MIMO system. Our study and simulation results show that the outage performance of a distributed antenna MIMO system can be significantly improved, when either increasing the number of distributed receive antennas or increasing the number of mobile transmit antennas

The newly observed Λb(6072)0\Lambda_b(6072)^0 structure and its ρ−\rho-mode nonstrange partners

Inspired by the newly observed $\Lambda_b(6072)$ structure, we investigate its strong decay behaviors under various assignments within the $^3P_0$ model. Compared with the mass and total decay width, our results suggest that the $\Lambda_b(6072)$ can be regarded as the lowest $\rho-$mode excitation in $\Lambda_b$ family. Then, the strong decays of $\rho-$mode nonstrange partners for the $\Lambda_b(6072)$ are calculated. It is found that the $J^P=5/2^-$ $\Lambda_b$ and $\Lambda_c$ states are relatively narrow, and mainly decay into the $\Sigma_b^{(*)} \pi$ and $\Sigma_c^{(*)} \pi$ final states, respectively. These two states have good potentials to be observed in future experiments, which may help us to distinguish the three-quark model and diquark model.Comment: 8 pages, 4 figures, comments and suggestions are welcom

Transition threshold in Ge x Sb 10 Se 90-x glasses

GexSb10Se90-x glasses with Ge content from 7.5 to 32.5at.% have been prepared by melt-quench technique, and the physical parameters including glass transition temperature (Tg), density (ρ), compactness (C), shear elastic moduli (Cs), compression elasti

Time-aware Multiway Adaptive Fusion Network for Temporal Knowledge Graph Question Answering

Knowledge graphs (KGs) have received increasing attention due to its wide applications on natural language processing. However, its use case on temporal question answering (QA) has not been well-explored. Most of existing methods are developed based on pre-trained language models, which might not be capable to learn \emph{temporal-specific} presentations of entities in terms of temporal KGQA task. To alleviate this problem, we propose a novel \textbf{T}ime-aware \textbf{M}ultiway \textbf{A}daptive (\textbf{TMA}) fusion network. Inspired by the step-by-step reasoning behavior of humans. For each given question, TMA first extracts the relevant concepts from the KG, and then feeds them into a multiway adaptive module to produce a \emph{temporal-specific} representation of the question. This representation can be incorporated with the pre-trained KG embedding to generate the final prediction. Empirical results verify that the proposed model achieves better performance than the state-of-the-art models in the benchmark dataset. Notably, the Hits@1 and Hits@10 results of TMA on the CronQuestions dataset's complex questions are absolutely improved by 24\% and 10\% compared to the best-performing baseline. Furthermore, we also show that TMA employing an adaptive fusion mechanism can provide interpretability by analyzing the proportion of information in question representations.Comment: ICASSP 202