Zhanqiang Huo

Modeling and performance evaluation for the sleep mode in the IEEE 802.16e wireless networks

IEEE 802.16e is the latest broadband wireless access standard designed to support mobility. In mobile networks, how to control energy consumption is one of the most important issues for the battery-powered mobile stations. The standard proposes an energy saving mechanism named ¿sleep mode¿ for conserving the power of the mobile stations. According to the operating mechanism of the sleep mode for downlink traffic in the type I power saving class, a discrete-time Geom/G/1 queueing model with a close-down time and multiple vacations is built in this paper. By employing an embedded Markov chain method, the average queue length and the average sojourn time of the system model are derived. Correspondingly, we get the performance measures of the energy saving rate and the average packet delay time for the sleep mode in the IEEE 802.16e. Finally, numerical results are given to demonstrate the dependency relationships between the system performance measures and the system parameters. Furthermore, a cost model is developed to determine the optimum length of the close-down time.

Performance Analysis and Evaluation for Connection-Oriented Networks Based on Discrete Time Vacation Queueing Model

Abstract In this paper, we establish a discrete time Geom/G/1 queue with setup/close-delay/close-down based on operating mechanism of Switch Virtual Channel Connection (SVCC) in connection-oriented networks. The formulas of SVCC performance measures of setup ratio, idle ratio, transmission efficiency and average response time are derived. Combining the formulas with system simulation, we confirm the dependency relationships between these performance measures and the close delay timer’s setting, which have potential applications in system optimal design and network control.

Modeling and performance evaluation of the sleep mode in the IEEE 802.16e wireless networks with self-similar traffic

Abstract IEEE 802.16e is currently the latest broadband wireless access standard designed to support mobility. In mobile networks, how to control energy consumption is one of the most important issues for battery-powered mobile stations. The standard proposes an energy saving mechanism named ‘sleep mode’ for conserving the power of mobile stations. According to the operation principle of the sleep mode for downlink traffic in the type I power saving class, considering the self-similar nature of massive multimedia data in wireless networks, a discrete-time batch arrival Geom X /G/1 queuing model with a close-down time and multiple vacations is built. The batch size is supposed to be Pareto distributed. By employing an embedded Markov chain method, the average queue length and the average sojourn time of the system model are derived. Correspondingly, the performance measures are obtained of the energy saving rate and the average packet delay time for the sleep mode in the IEEE 802.16e. The numerical results demonstrate the dependency relationships between the system performance measures and the system parameters with different offered loads and different self-similar degrees. Furthermore, a cost model is developed to determine the optimum length of the close-down time for minimizing the total system cost.

Performance Evaluation of ARQ Schemes for Service-Oriented Internet in Wireless Networks

In this paper, we analyze the performance of automatic repeat request (ARQ) schemes for the service-oriented Internet in wireless networks. Considering the self-similar nature of a massive-scale multimedia service shown in Internet traffic, in this paper we present a discrete-time system operating on the basis of time slotting with a batch arrival. Moreover, taking into account the delay in the setting up procedure of the channels, we introduce a setup strategy in this system model. In the performance analysis, firstly, by using an imbedded Markov chain, we derive the probability generation functions (P.G.Fs.) of the queueing length, the waiting time and the busy period of the system. Then, we use these analyses to give some important performance measurements for wireless networks using ARQ schemes in terms of the response time and the setup ratio for the self-similar traffic. In numerical results, we make some comparisons such as the response time and the setup ratio with the systems by using other previously known ARQ schemes having the memoryless traffic to show the influence of the self-similar degree on the system performance.

Performance evaluation of a connection-oriented Internet service based on a queueing model with finite capacity

The operating mechanism of a connection-oriented Internet service is analyzed. Considering the finite buffer in connection-oriented Internet service, we establish a Geom/G/1/K queueing model with setup-close delay-close down for user-initiated session. Using the approach of an embedded Markovian chain and supplementary variables, we derive the probability distribution for the steady queue length and the probability generating function for the waiting time. Correspondingly, we study the performance measures of quality of service (QoS) in terms of system throughput, system response time, and system blocking probability. Based on the simulation results, we discuss the influence of the upper limit of close delay period and the capacity of the queueing model on the performance measures, which have potential application in the design, resource assigning, and optimal setting for the next generation Internet.

Simulation Study of a Connection-Oriented Internet Service Based on a Queueing Model

In this paper, we analyze the operating mechanism of a connection-oriented Internet service. Considering the finite buffer size in a connection-oriented Internet service, we establish a Geom/Geom/1/K queueing model with setup-close delay-close down feature for user-initiated sessions. Using a simulation approach, we study the performance measures of Quality of Service (QoS) in terms of system throughput, system response time, and system blocking probability. Based on the simulation results, we discuss the influence of the upper limit of close delay period and the capacity of the buffer on the performance measures. Findings from such an analysis may potentially be applied in the design, resource assigning, and optimal setting for the next generation Internet.