Presently, optical burst switching (OBS) technology is under study as a promising solution for the backbone of the optical Internet in the near future because OBS eliminates the optical buffer problem at the switching node with the help of no optical/electro/optical conversion and guarantees class of service without any buffering. To implement the OBS network, there are a lot of challenging issues to be solved. The edge router, burst offset time management, and burst assembly mechanism are critical issues. In addition, the core router needs data burst and control header packet scheduling, a protection and restoration mechanism, and a contention resolution scheme. In this paper, we focus on the burst assembly mechanism. We present a novel data burst generation algorithm that uses hysteresis characteristics in the queueing model for the ingress edge node in optical burst switching networks. Simulation with Poisson and self‐similar traffic models shows that this algorithm adaptively changes the data burst size according to the offered load and offers high average data burst utilization with a lower timer operation. It also reduces the possibility of a continuous blocking problem in the bandwidth reservation request, limits the maximum queueing delay, and minimizes the required burst size by lifting up data burst utilization for bursty input IP traffic.

We propose new ergodic interference alignment techniques for K-user interference channels with delayed feedback. Two delayed feedback scenarios are considered -delayed channel information at transmitter (CIT) and delayed output feedback. It is proved that the proposed techniques achieve total 2K/(K + 2) DoF which is higher than that by the retrospective interference alignment for for the delayed feedback scenarios. Index TermsInterference channel, degrees of freedom (DoF), ergodic interference alignment, delayed feedback.

No abstract

No abstract

This paper proposes a novel service differentiation mechanism utilizing optical buffers in transparent optical networks. We first introduce fiber delay line (FDL)-based optical buffers and propose a hybrid shared optical buffered node. Based on the proposed buffer, diverse service requirements can be satisfied by assigning different priorities on accessing the buffer. Since the blocking performance is affected by the basic delay unit of FDL represented by a ratio of the burst length, this paper also takes into account the effect of the burst assembly process on the buffer performance. By dynamically adjusting the burst length under the changing traffic load, optimal performance of the proposed optical buffer can be achieved. Our simulation results show that diverse service requirements can be satisfied in terms of burst blocking probability and buffering delay time.

No abstract

No abstract

We evaluate and compare the performance of timer-based and threshold-based assembly algorithms in Optical Burst Switching networks. Results including burst blocking probability, mean packet delay and link utilization at the ingress node are presented from both simulations and two theoretical models. The results are obtained for the full range of input traffic load so they can provide guidelines for design and dimensioning links to meet desired Quality of Service levels.