Beijing University of Posts and Telecommunications

About: Beijing University of Posts and Telecommunications is a education organization based out in Beijing, Beijing, China. It is known for research contribution in the topics: MIMO & Quality of service. The organization has 39576 authors who have published 41525 publications receiving 403759 citations. The organization is also known as: BUPT.

Successive interference cancelation amenable multiple access (SAMA) for future wireless communications

Abstract: In this work, we introduce a novel multiple access scheme which is based on the joint design of the system signature matrix at the transmitter and the successive interference cancelation (SIC) based detector at the receiver. The symbols of the different users are judiciously spread in the frequency (space) domain, which can be effectively exploited by the SIC based technique, such as the iterative message-passing algorithm (MPA), to cancel the multi-user interference as well as to obtain diversity gain. Numerical results show that the non-orthogonal system based on the proposed successive interference cancelation amenable multiple access (SAMA) paradigm employing the iterative MPA achieves significant performances gain over the orthogonal one for the same spectral efficiency with affordable complexity.

Dynamical Clustering in Electronic Commerce Systems via Optimization and Leadership Expansion

Abstract: In many electronic commerce systems, detecting significant clusters is of great value to the analysis, design, and optimization of the commerce behaviors. In this article, we propose a new dynamical approach to detect the cluster configuration fast and accurately which can be applied to electronic commerce systems. First, we analyze the two-stage game in which the leader group members make contributions prior to the follower group, and propose an exact index, i.e., the leadership , to characterize the key leaders. Then an efficient dynamical system is used to guarantee the cluster configuration converges to an optimal state, which assigns each node to the corresponding cluster based on quality optimization, repeatedly. Our method is of high efficiency—the exponential term in the proposed dynamical system makes the convergence to be very fast with a nearly linear time. Extensive experiments on multiple types of datesets demonstrate the state-of-the-art performance of proposed method.

Design and Performance Analysis of An Energy-Efficient Uplink Carrier Aggregation Scheme

Abstract: Energy efficiency is of vital importance for telecommunications equipment in future networks, especially battery-constrained mobile devices. In the long term evolution-Advanced (LTE-Advanced) network, the carrier aggregation (CA) technique is employed to allow user equipment (UE) to use multiple carriers for high data rate communications. However, multi-carrier transmission entails increased power consumption at user devices in uplink networks. In this paper, we propose a new dynamic carrier aggregation (DCA) scheduling scheme to improve the energy efficiency of uplink communications. Two scheduling methods, i.e., serving the longest queue (SLQ) and round-robin with priority (RRP), are designed to reduce transmit power while maximizing the utilization of wireless resources. The proposed scheme is analyzed in terms of both the data rate and energy conservation. We build an ideally balanced system (IBS) to investigate the performance upper bound of the DCA scheme, and derive closed-form expressions. Simulation results demonstrate that the proposed scheme can not only enhance the energy efficiency but also perform closely to the optimal IBS.

Load Balancing in Data Center Networks: A Survey

Abstract: Data center networks usually employ the scale-out model to provide high bisection bandwidth for applications. A large amount of data is required to be transferred frequently between servers across multiple paths. However, traditional load balancing algorithms like equal-cost multi-path routing are not suitable for rapidly varying traffic in data center networks. Based on the special data center topologies and traffic characteristics, researchers have recently proposed some novel traffic scheduling mechanisms to balance traffic. In this paper, we present a comprehensive survey of recent solutions for load balancing in data center networks. First, recently proposed data center network topologies and the studies of traffic characteristics are introduced. Second, the definition of the load-balancing problem is described. Third, we analyze the differences between data center load balancing mechanisms and traditional Internet traffic scheduling. Then, we present an in-depth overview of recent data center load balancing mechanisms. Finally, we analyze the performance of these solutions and discuss future research directions.

Ergodic Capacity Analysis of Remote Radio Head Associations in Cloud Radio Access Networks

Abstract: Characterizing user to remote radio head (RRH) association strategies in cloud radio access networks (C-RANs) is critical for performance optimization. In this letter, the single nearest and N-nearest RRH association strategies are presented, and the corresponding impact on the ergodic capacity of C-RANs is analyzed, where RRHs are distributed according to a stationary point process. Closed-form expressions for the ergodic capacity of the proposed RRH association strategies are derived. Simulation results demonstrate that the derived uplink closed-form capacity expressions are accurate. Furthermore, the analysis and simulation results show that the ergodic capacity gain is not linear with either the RRH density or the number of antennas per RRH. The ergodic capacity gain from the RRH density is larger than that from the number of antennas per RRH, which indicates that the association number of the RRH should not be bigger than 4 to balance the performance gain and the implementation cost.