Xiaowen Liang

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We obtain the expression and a lower-bound for area spectral efficiency (ASE) of single-tier Poisson distributed networks considering multiuser MIMO (MU-MIMO) transmission. With the help of the lower-bound, we observe some interesting results. These results are validated via numerical results for the original expression. We find that ASE can be viewed as a(More)
This paper considers the joint small cells (SCs) on/off and load balancing (LB) design in dense heterogeneous networks (HetNets). We aim to maximize the network energy efficiency (NEE), defined as the network throughput divided by the total energy consumption (EC), subject to the rate fairness constraints among users. This problem is NP-hard and thus is(More)
Splitting the control plane (C plane) and data plane (D plane) is a key feature of future cellular networks. This letter studies the energy-efficient deployment strategy to guarantee the coverage and throughput of functionality separated network. While previous works mostly focused on single-antenna networks, our focus is the performance and energy(More)
In this paper we propose an algorithm to optimize the network-level delay based on flow-level model, denoted as flow-level delay, in fractional frequency reuse (FFR) cellular networks. The flow-level model can capture the impact of the dynamic traffic in the network by considering the arrival and departure of the traffic flows in all cells. In addition to(More)
In this letter, the delay-aware uplink user association problem in conjunction with power control is considered for energy efficiency in heterogeneous cellular networks. We aim at minimizing the energy consumption of user terminals under the delay constraints. Due to the mutual interference and the coupled queue dynamics, the problem is NP-hard and thus is(More)
It is assumed that all associated parameters, concerning factors and workflows are deterministic in the classical definition about field engineering. But this conception usually is too simplistic to meet increasing requirements to raise the efficiency of production and service, especially for the fast developing and more elaborate fleet of trucks. The(More)
Quad-tree index has been widely used in geo-spatial database management and GIS. Yet, how to determine a suitable index depth of quad-tree for an optimal query in terms of query speed remains a difficult task. Bearing this task in mind, the authors analyze the close correlation between the index depth and the index range. The query efficiency of quad-tree(More)
License Plate Recognition (LPR) combines computer vision technology and pattern recognition technology and plays an important role in Freeway Toll System, Urban Road Monitoring System and the Intelligent Parking Lot Management System. Therefore, it has attracted an ever increasing number of scholars from home and abroad. Despite many years of unremitting(More)
Sparse code multiple access system with multiple antennas offers unprecedented massive connectivity and capacity. To reduce the interference in a downlink multiple user SCMA (MU-SCMA) system, we propose a layer-aware interference mitigation scheme (L-AIMS). Firstly, preprocess the codewords of paired users to mitigate the intra-layer interference. Secondly,(More)