A Study Of Optical Network RWA Algorithm Based On Physical Layer Impairments Constraints

In the recent years, the architecture of optical networks is evaluate gradually towards all-optical(transparent) networks. In transparent networks, there is no elec-regenerators anymore, the impairments from the non-ideal optical components and devices accumulate along the lightpath and causing the signal distortion. In the high-speed future networks, how to make the optical signal to avoid the damage of a variety of physical layer impairments during the transmission in the optical fiber and meeting the QoT(Quality of Transmission) of the variety services is a urgent solution problem. So the issue that the RWA(Routing and wavelength assignment) algorithm based on physical layer impairments constraints became more and more concerning.In this context, this paper analysis the physical layer impairment model and the key issues of the physical layer impairments aware RWA algorithm, a multi-constraint based physical layer model is structured, and based on the model, a new RWA algorithm based on multiple physical layer impairments constraints is proposed, that will provides more comprehensive solution way to the impairments constraint RWA problems. Major work is divided into the following sections:(1) The variety of physical layer impairments in transparent networks has been studied. First analysis the main optical devices in the transmission networks, then investigate the more and more complicated effects from the non-ideal optical components and devices under the premise of continuous development of the transparent networks.(2) This paper analyses the recent issue of considering physical impairment in impaired-aware optical network relatively simple. On these bases, a physical model is proposed that multi-physicals are quantified to the OSNR degradation along the optical signal propagation. This model is consider the miscellaneous items of physical impairment, therefore it could be evaluate the physical impairment status of the optical light path more accurately.(3) A new kind of RWA algorithm based on multiple physical layer impairments constraints is proposed to improve the issue of considering physical impairment relatively simple, attempt to use multiple physical impairments as multiple constraints, thereby could choose the least impact optical path to accomplish the linking request, meeting the requirement of the higher transmission quality in future networks. At last, the thesis stimulates the algorithm we proposed and the result shows that comparead with the exsting algorithm, the new one increases 5%-10% better in blocking rate.