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695 results on '"Caijun Zhong"'

1. Adaptive Channel Estimation and Tracking for URA-Based Massive MIMO Systems

Author

Rui Yin, Xin Zhou, Anding Wang, Caijun Zhong, Celimuge Wu, and Xiaoming Chen

Subjects
2D massive MIMO systems, 3D channel estimation, direction of arrival (DoA), PSA, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

In this paper, an adaptive channel estimation and tracking method is proposed for the uniform rectangular array (URA) based massive multiple-input and multiple-output (M-MIMO) systems. To decrease the computational complexity while tracking the change on the channel state information (CSI) in time, a principal subspace analysis (PSA) based scheme is proposed to estimate and track the signal subspace based on the received signal covariance matrix. Based on the estimated signal subspace, the channel parameters including the direction of arrival (DoA) angle and the channel gain corresponding to each resolvable path of the channel, can be recovered via the classic multiple signal classification (MUSIC) algorithm. Then, the Cramer-Rao lower bound (CRLB) is derived to evaluate the performance of the proposed scheme. Simulation results are provided to verify the accuracy of the proposed scheme on the channel estimation.

Published
2020
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2. On the Capacity Scaling of Large Multipair Relay Networks With Successive Relaying Protocol

Author

Yu Zhang, Zhaoyang Zhang, Li Ping, Xiaoming Chen, and Caijun Zhong

Subjects
Large relay networks, capacity scaling law, successive relaying protocol, amplify-and-forward, Electrical engineering. Electronics. Nuclear engineering, TK1-9971
Abstract

In this paper, we consider large multi-pair relay networks with K fixed source-destination pairs and M relays randomly distributed in a given area, where each node is equipped with a single antenna and works on half duplex. Each source communicates with its corresponding destination under the aid of the relays. With the conventional two-slot relaying protocol, the sum capacity was found to scale as (K/2) log(M) + O(1), where K is fixed and M → ∞. This paper proves that the capacity scaling law can be further improved to K log(M) + O(1) with successive relaying protocol, as if the relays became "full duplex." To prove the scaling law, a distributed amplify-and-forward scheme is proposed, which only requires local channel state information (CSI) at each relay and statistical global CSI at the sources and destinations. Furthermore, we prove that imperfect CSI at the relays would not affect the scaling law.

Published
2017
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3. Single Gas Permeance Performance of High Silica SSZ-13 Zeolite Membranes

Author

Li Liang, Meihua Zhu, Le Chen, Caijun Zhong, Yiming Yang, Ting Wu, Heli Wang, Izumi Kumakiri, Xiangshu Chen, and Hidetoshi Kita

Subjects
high silica SSZ-13 zeolite membrane, aluminum-free, single gas permeance, CO2, CH4, Chemical technology, TP1-1185, Chemical engineering, TP155-156
Abstract

Continuous and high silica SSZ-13 zeolite membranes were prepared on porous mullite supports from high SiO2/Al2O3 ratio or aluminum-free precursor synthesis gel. Single gas permeance (CO2 and CH4) of the high silica SSZ-13 zeolite membrane was decreased with the SiO2/Al2O3 ratio in the precursor synthesis gel, while the ideal CO2/CH4 selectivity of the membrane was gradually increased. Moreover, effects of synthesis conditions (such as H2O/SiO2 and RNOH/SiO2 ratios of precursor synthesis gel, crystallization time) on the single gas permeance performance of high silica SSZ-13 zeolite membranes were studied in detail. Medium H2O/SiO2 and RNOH/SiO2 ratios in the initial synthesis gel were crucial to prepare the good CO2 perm-selective SSZ-13 zeolite membrane. When the molar composition of precursor synthesis gel, crystallization temperature and time were 1.0 SiO2: 0.1 Na2O: 0.1 TMAdaOH: 80 H2O, 160 °C and 48 h, CO2 permeance and ideal CO2/CH4 selectivity of the SSZ-13 zeolite membrane were 0.98 × 10−7 mol/(m2·s·Pa) and 47 at 25 °C and 0.4 MPa. In addition, the SiO2/Al2O3 ratio of the corresponding SSZ-13 zeolite was 410 by X-ray fluorescence spectroscopy.

Published
2018
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