This paper studies a constrained optical signal-to-noise ratio (OSNR) optimization problem in optical networks from the perspective of system performance. A system optimization problem is formulated with the objective of achieving an OSNR target for each channel while satisfying the total power constraint. In order to establish existence of a unique optimal solution, the conditions are derived, which can be used as a basis for an admission control scheme. The original problem is then converted to a relaxed system problem by using a barrier function and solved by a distributed iterative algorithm. Next, the system optimization framework developed is compared to the game theoretic one in [1]. The effects of parameters in both formulations are investigated to study efficiency of Nash equilibria in the OSNR game and pricing mechanisms affecting overall system performance. The theoretical analysis is supported by numerical simulations and experiments conducted on an optical fiber link.

This paper develops a Nash game towards optimizing optical signal-to-noise ratio (OSNR) in the presence of link capacity constraint. In optical wavelength-division multiplexing (WDM) networks, all wavelength-multiplexed channels in a link share the optical fiber. In order to limit nonlinear effects, the total power launched into a fiber has to be below a nonlinearity threshold. This can be regarded as the optical link capacity constraint. We formulate an extended OSNR Nash game that incorporates this underlying system constraint. The status of an optical link is considered directly in the cost function. Sufficient conditions for existence and uniqueness of the Nash equilibrium (NE) solution are given. Two iterative algorithms for channel power control are proposed to compute the NE solution: a parallel update algorithm (PUA) and a relaxed PUA (r-PUA). Their convergence is studied under different conditions, both theoretically and numerically.

We study the optical signal-to-noise ratio (OSNR) optimization problem in optical wavelength-division multiplexed (WDM) networks. This work extends our previous results in [1] on games with coupled constraints in optical links to generic WDM networks. We first develop a model for the network and an OSNR model for each link by investigating the interaction between the network and physical layers. The nonlinear threshold is considered as the link capacity constraint and we study the case in which channel powers are adjustable at the switching nodes. We formulate an OSNR Nash game with coupled utilities and constraints. Each player (channel) in the game maximizes its own utility function which is related to minimizing the individual OSNR degradation. We exploit this OSNR Nash game in two typical network topologies: multi-link topology and quasi-ring topology. The hierarchical decomposition approach leads to a lower-level game for channels with no coupled constraints and a higher-level optimization problem for the network.

This paper considers the problem of optical signal-to-noise ratio (OSNR) optimization with link capacity constraints within a Nash game framework. In optical wavelength-division multiplexed (WDM) networks, all wavelength-multiplexed channels share the optical fiber. Even when individually channel parameters are adjusted, the total launched power has to be limited below the nonlinearity threshold. This can be regarded as the optical link capacity constraint. In the previous work of Pan & Pavel (2005), the authors have proposed an extended OSNR Nash game. Channel utility has been related to OSNR and the status of the optical link has been considered directly in channel cost function. The difficulty is that the unique Nash equilibrium (NE) solution of this OSNR Nash game is highly nonlinear and thus analytically intractable. The main contribution of this paper is to develop an iterative, distributed gradient algorithm towards finding the NE solution. The algorithm uses only local measurements and the current load of the network (or link). The authors proved that the iterative gradient algorithm converges globally to this NE solution under sufficient conditions.