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454 results on '"Yang, Dacheng"'

10. On Buffer-Constrained Throughput of a Wireless-Powered Communication System.

Author

Li, Zhidu, Jiang, Yuming, Gao, Yuehong, Sang, Lin, and Yang, Dacheng

Subjects
WIRELESS communications, ENERGY harvesting, STORAGE batteries
Abstract

In this paper, the buffer-constrained throughput performance of a multi-user wireless-powered communication (WPC) system is investigated, where energy harvesting follows a non-linear model. The investigation focuses on the buffer overflow performance of sending data in the downlink (DL) from the access point (AP) node to each user equipment (UE) node and that in the uplink from each UE node to the AP node, based on which the throughput performance on both directions when a buffer constraint is enforced is studied. Specifically, the buffer overflow probability at each node is analyzed, based on which the buffer-constrained throughput is studied. In addition, to ensure the throughput performance under the buffer constraint, the DL transmission power allocation policy and the required energy storage capacity at each UE are investigated. Also, the optimal channel time allocation policy is studied with the objective of maximizing the minimum buffer-constrained throughput guaranteed to each UE at the same time. To this aim, an optimization problem is first formulated and then a dichotomy-based time allocation algorithm combined with a one-dimensional search is proposed to solve this problem. The analysis and results, explicitly relating the throughput to the buffer constraint in addition to WPC characteristics, shed new light on the design and performance analysis of WPC systems. [ABSTRACT FROM AUTHOR]

Published
2019
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38. Research on Rate Allocation Schemes for the Reverse Link in CDMA2000 System

Author

Liu Bingzhang, Yang Dacheng, and Zhang Xin

Subjects
Scheme (programming language), Computer engineering, Computer science, business.industry, Quality of service, CDMA2000, Overhead (computing), Communications system, Link (knot theory), business, computer, computer.programming_language, Computer network
Abstract

This paper focuses on the rate allocation schemes on the reverse link (RL) of CDMA2000 1xEV-DV system. Two schemes, the time-scheduled (TS) scheme and the rate-controlled (RC) scheme are described and compared. Based on their pros and cons, we propose a modified version to bring together the merits of the two schemes. The proposed scheme, which is called Multi-Step-up RC scheme, can enable a mobile to increase its rate by multiple steps when needed. The TS scheme, RC scheme and the proposed scheme are respectively simulated on our CDMA2000 1xEV-DV Release D reverse link system level simulation platform. Our simulation results show that the proposed scheme can efficiently utilize the radio resource and improve the user?s QoS performance of delay. In addition, the performance gain is achieved using the same amount of signaling overhead as that of RC scheme, which is much less than that of TS scheme. The idea of the proposed scheme can be applied to other similar communication systems.

Published
2006

39. A Prediction-Based Smoothing Scheme for Real-Time Video Transmission in 3G CDMA Systems

Author

Zhang Xin, Liu Bingzhang, Qin Jie, and Yang Dacheng

Subjects
Transmission (telecommunications), Code division multiple access, Computer science, Quality of service, Real-time computing, Physical layer, Signal, Smoothing, Group of pictures, Communication channel
Abstract

A prediction-based smoothing scheme for real-time video transmission in 3G CDMA systems is proposed in this paper. It is carried out within group of pictures (GOP), using data prediction method to reduce delay, setting the minimum rate based on delay requirement, and choosing transmission rate among CDMA physical layer rate sets. This scheme can considerably reduce the peak rate and variance of the transmitted signal. Furthermore, we proposed a scheduling algorithm combining smoothing scheme and channel quality. Simulation results show that with the proposed smoothing scheme, higher system stability and better QoS have been achieved. Moreover, the system performance gain is more considerable when the channel condition is relatively poor. The scheduling algorithm can well adapt to channel quality to utilize system resource efficiently with the QoS requirement.

Published
2006

40. Evaluation Methodology for Fast Switching Cloud RAN Systems.

Author

Wang, Yaxin, Zhang, Xin, and Yang, Dacheng

Abstract

The switching scheme between base band units (BBUs) and remote radio heads (RRHs) is a key point in a cloud radio access network (C-RAN). Fast BBU-RRH switching schemes will play crucial roles in future flexible C-RAN systems. In this letter, an evaluation model is proposed to analyze the performance of fast switching schemes. Based on the model, we also propose an evaluation methodology through jointly taking backlogs, idle resources, and switching costs into account. The evaluation methodology provides guidance on future design for fast switching schemes. Finally, the effectiveness of the proposed methodology is validated by simulation results. [ABSTRACT FROM PUBLISHER]

Published
2017
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41. An adaptive rate control scheme based on reverse pilot power distribution for CDMA systems

Author

Zhang Xin, Zhang Yong, Yang Dacheng, and Qin Jie

Subjects
Engineering, Rise over thermal, Adaptive control, Control theory, business.industry, Mobile station, CDMA2000, Electronic engineering, Throughput, business, Transmitter power output, Return channel, Communication channel
Abstract

The mechanism of the reverse link (RL) data rate control in a CDMA system is studied, and a new scheme is presented to enhance the efficiency, which is based not only on a probabilistic model, but also on a variable signifying the competitive ability of the mobile station (MS). This variable is related to the distribution of MS's reverse pilot transmit power, which can reflect its reverse channel quality compared with other MSs in some sense. With this new mechanism, The MS enjoying better channel quality is easier in raising its data transmission rate while the MS undergoing worse channel quality is more likely to reduce its rate. Since MS's reverse pilot transmit power is a variable known by MS itself, no extra signaling overhead is required from BS. Through dynamic system level simulation for CDMA2000 release D where H-ARQ is employed on RL, the results show that the system throughput on RL is improved by the proposed scheme with the rise over thermal (RoT) value kept on a stable level

Published
2005

42. Dynamic Uplink Radio Access Selection of LTE Licensed-Assisted Access to Unlicensed Spectrum: An Optimization Game.

Author

Zhang, Meng, Zhang, Xin, Chang, Yongyu, and Yang, Dacheng

Abstract

Licensed-assisted access (LAA) to unlicensed spectrum has drawn the worldwide attention from academia and industry since its emergence at the Third Generation Partnership Project in 2015. As a key technology for Long Term Evolution unlicensed spectrum deployment, LAA goes far toward solving the coexistence problems in the 5-GHz unlicensed bands. However, owing to unpredictable interference from unlicensed-band opponent systems, for example, WiFi, LAA uplink transmission may suffer from serious inefficiency in scheduling-based radio access. To tackle such an issue, this letter proposes a dynamic uplink radio access selection scheme between scheduling and random access for LAA uplink transmission. Next, in order to exploit optimum performance, an optimization game of the uplink radio access selection is formulated. Last but not least, the optimum solution of the game is proved to exist by potential game theory, laying instructive foundations for LAA uplink standardizations. [ABSTRACT FROM PUBLISHER]

Published
2016
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