Browsing by Subject "Switching delay"
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Item Open Access Average capacity maximization via channel switching in the presence of additive white Gaussian noise channels and switching delays(Institute of Electrical and Electronics Engineers Inc., 2016) Sezer, A. D.; Gezici, SinanThe optimal channel switching problem is studied for average capacity maximization in the presence of additive white Gaussian noise channels and channel switching delays. First, an optimization problem is formulated for the maximization of the average channel capacity, considering channel switching delays and constraints on average and peak powers. Then, an equivalent optimization problem is obtained to facilitate theoretical investigations. The optimal strategy is derived and the corresponding average capacity is specified when channel switching is performed among a given number of channels. Based on this result, it is shown that channel switching among more than two different channels is not optimal. In addition, the maximum average capacity achieved by the optimal channel switching strategy is formulated as a function of the channel switching delay parameter and the average and peak power limits. Then, scenarios under which the optimal strategy corresponds to the exclusive use of a single channel or to channel switching between two channels are described. Furthermore, sufficient conditions are obtained to determine when the optimal single channel strategy outperforms the optimal channel switching strategy. The numerical results are presented to provide the examples of the theoretical results and to illustrate the effects of channel switching delays. © 2002-2012 IEEE.Item Open Access Dynamic wavelength allocation in IP/WDM metro access networks(Institute of Electrical and Electronics Engineers, 2008-04) Yetginer, E.; Karasan, E.Increasing demand for bandwidth and proliferation of packet based traffic represent a challenge for today’s metro networks, which have been traditionally designed to carry circuitswitched connections. The problem is further complicated by the constraints of cost efficiency and traffic adaptability, imposed by the limited customer base in the metro area. Recently, several architectures have been proposed for future metro access networks. Nearly all of these solutions support dynamic reconfigurability, however reconfiguration policies have not been fully explored yet. In this paper, reconfiguration policies for IP/WDM metro access networks with switching delays are considered, where dynamic reconfiguration corresponds to dynamic allocation of wavelengths to access nodes. Exact formulation of the dynamic wavelength allocation (DWA) problem is developed as a Markov Decision Process (MDP) and a new cost function is proposed to attain both throughput efficiency and fairness. For larger problems, a heuristic approach based on first passage probabilities is developed and shown to yield nearly optimum performance through simulations.Item Open Access Optimal channel switching for average capacity maximization in the presence of switching delays(IEEE, 2016) Sezer, Ahmet Dündar; Gezici, SinanIn this study, the optimal channel switching problem is investigated for average capacity maximization in the presence of channel switching delays. First, the optimal strategy is obtained and the corresponding average capacity is derived when channel switching is performed among a given number of channels. Then, it is proved that channel switching among more than two different channels is not optimal. Also, the maximum average capacity achieved by the optimal channel switching strategy is expressed as a function of the channel switching delay parameter and the average and peak power limits. Then, scenarios in which the optimal strategy corresponds to the use of a single channel or to channel switching between two channels are described. Numerical examples are presented for showing the effects of channel switching delays.