Journées de l'optimisation 2007 Optimizations days

Convolutional Self-Doubly Orthogonal Codes (CSO^2C) have been introduced in 1998 by Haccoun et al. as a novel class of convolutional codes which can be decoded using an iterative threshold decoding algorithm that does not require interleavers. However these codes need to satisfy some orthogonality properties. Moreover the memory length of the code is a key issue for their overall latency. Unfortunately, the design of CSO^2C codes with minimum span corresponds to a highly combinatorial problem and only heuristics have been proposed up to now. We present different mathematical programming formulations for the design of CSO^2C codes with minimum span. Solving the continuous relaxation of these formulations yields lower bounds, that we use to assess the quality of the heuristics.

We compare two established approaches to OSNR optimization in optical networks and point out a joint optimization framework with an optimal prechirping parameter for dispersion management. We will also propose a second-order mixed strategy and algorithm that will combine the properties of these two approaches to achieve a parametric, fast converging and efficient power control mechanism.

In this paper, we propose a joint routing and admission control mechanism for the IP traffic flows in MPLS (Multiprotocol Label Switching) networks without rerouting. We avoid rerouting because it may be service affecting. The solutions are obtained by solving exactly a mathematical programming model including end-to-end packet loss constraints for all traffic flows. The objective of the model is to minimize end-to-end delay while respecting packet loss constraints for every flow without rerouting. Numerical results show that this proposed model can be solved rapidly even for real-size instances of the problem.

In this paper, we propose a tabu search algorithm for the planning problem of wireless local area networks. The problem consists of selecting the location, the transmit power, the antenna and its orientation as well as the communication channel of the access points in the network. For every user, minimal throughput and tolerable interference levels are guaranteed. The results show that quasi-optimal solutions can be obtained with the proposed approach.