Guojun Dong

Bio: Guojun Dong is an academic researcher from Tianjin University. The author has contributed to research in topics: Channel allocation schemes & Energy consumption. The author has an hindex of 2, co-authored 2 publications receiving 14 citations.

Power Saving Class I Sleep Mode in IEEE802.16e System

Abstract: This paper investigates energy saving of MS (mobile subscriber) at power saving class I sleep mode in IEEE 802.16e system. In order to minimize the MS power consumption and decrease the occupation of interface resources in serving BS (base station), the sleep mode mechanism is introduced. This paper models the energy consumption of power saving class I sleep mode under the consideration of sleep interval of variable power rather than a constant power, and two-type-returning from sleep mode. Simulation results show that the effect of power saving class I sleep mode varies depending on different parameter configurations.

Dynamic Frequency Selection (DFS) in IEEE802.16e OFDM System Working at Unlicensed Bands

Abstract: This paper investigates the dynamic frequency selection (DFS) scheme in IEEE 80216e OFDM (orthogonal frequency division multiplexing) system working at unlicensed bands Working at unlicensed bands, the IEEE 80216e OFDM system devices are liable to suffer from additional interference generated by physical channel collision The DFS is a good mechanism to overcome this co-existence issue, and is mandatory for unlicensed bands operation in IEEE 80216e specification Compared with the static frequency selection scheme defined in IEEE 80216e specification, a particular DFS scheme is proposed for unlicensed bands operation The Simulation results prove that the performances of system capacity and BER of the IEEE 80216e OFDM system are improved greatly using the proposed DFS scheme

OFDM for cognitive radio: merits and challenges

Abstract: Cognitive radio is a novel concept that enables wireless systems to sense the environment, adapt, and learn from previous experience to improve the quality of the communication. However, CR requires a flexible and adaptive physical layer in order to perform the required tasks efficiently. In this article, CR systems and their requirement of a physical layer are discussed, and the orthogonal frequency division multiplexing technique is investigated as a candidate transmission technology for CR. The challenges that arise from employing OFDM in CR systems are identified. The cognitive properties of some OFDM-based wireless standards also are discussed to indicate the trend toward a more cognitive radio.

An Efficient Power Saving Mechanism for Delay-Guaranteed Services in IEEE 802.16e

Abstract: As the IEEE 802.16e Wireless Metropolitan Access Network (WMAN) supports the mobility of a mobile station (MS), increasing MS power efficiency has become an important issue. In this paper, we analyze the sleep-mode operation for an efficient power saving mechanism for delay-guaranteed services in the IEEE 802.16e WMAN and observe the effects of the operating parameters related to this operation. For the analysis we use the M/GI/1/K queueing system with multiple vacations, exhaustive services and setup times. In the analysis, we consider the power consumption during the wake-mode period as well as the sleep-mode period. As a performance measure for the power consumption, we propose the power consumption per unit time per effective arrival which considers the power consumption and the packet blocking probability simultaneously. In addition, since we consider delay-guaranteed services, the average packet response delay is also considered as a performance measure. Based on the performance measures, we obtain the optimal sleep-mode operation which minimizes the power consumption per unit time per effective arrival with a given delay requirement. Numerical studies are also provided to investigate the system performance and to show how to achieve our objective.

An Adaptive Cluster-Based Routing Mechanism for Energy Conservation in Mobile Ad Hoc Networks

Abstract: In recent years, many studies have proposed various ways to strengthen wireless networks' performance. In this paper, we identify some drawbacks arising from protocol improved location-aided routing (ILAR). Nodes around the borders of a given broadcast coverage might quickly and easily move out, resulting in a broken routing path. Another problem in ILAR is that, although it may have a better forwarding node available for use a relay node could fail. Therefore we propose a novel routing protocol integrated power balance scheme to help resolve the problems mentioned above. Furthermore, the scheme employs position information and a power-saving scheme to balance the energy of each node and to lengthen the entire network's life. To achieve these goals, there must be a reduction in the simultaneous loading of networks. Therefore, we also propose a cluster-based routing mechanism in mobile ad hoc networks. This mechanism can reduce the loading of networks, energy conservation, and increase the lifetime of nodes and networks.

Performance analysis for queueing systems with close down periods and server under maintenance

Abstract: A single server queue subject to maintenance of the server and the close down period is considered. We obtain explicit expressions for the transient probabilities of the system size, the server under maintenance state and the close down period. The time-dependent performance measures of the system and the probability density function of the first-passage-time to reach the maintenance state are discussed. The corresponding steady state analysis and key performance measures of the system are also presented. Finally, the effect of various parameters on system performance measures is demonstrated by a numerical example.

Performance analysis of sleep mode operation in IEEE802.16e

Abstract: The IEEE80216e is a standard of emerging broadband wireless access system which supports the mobilityThe mobile subscribers(MSS) are mainly powered by the batteries,so the sleep mode mechanism becomes an important component for the MSS which can effectively manage the limited energy,and prolong the using time of the once-charged batteriesThis paper introduced the standardized sleep mode in IEEE80216e,then it analyzed the average energy consumption and the average packet delay under sleep mode by building a semi-Markov chain,and gave the simulation results by NS2 at last