In this work, we provide analytical insights into physical architectures that can serve as benchmarks for designing cost-efficient WDM metropolitan area networks (MANs). For analytical simplicity, we restrict our attention to uniform all-to-all traffic and regular topologies with nodal symmetry. By formulating a first-order cost model and characterizing the tradeoff between fiber and switching resources, we identify a class of regular graphs - generalized Moore graphs - that have attractive properties for MAN designs. Our previous and new results show that, in conjunction with minimum hop routing (which is shown to be optimal), Moore Graphs (special cases of Generalized Moore Graphs) achieve the minimum cost and simultaneously use the least number of wavelengths. We also broaden the scope of our work by addressing irregular network topologies, which represent most existing networks. We show that our results on networks that are generalized Moore networks can be used to provide useful estimates of the cost of irregular networks. These properties indicate that generalized Moore graphs and their close relatives are good reference architectures for the designs of practical networks.

Managing the peak-to-mean envelope power ratio (PMEPR) of orthogonal frequency-division multiplexed (OFDM) transmissions is a difficult but essential problem for practical and low-cost applications of OFDM. A promising coding technique generates OFDM signals from Golay complementary sequences in first-order Reed-Muller (RM) codes. In this paper we will construct a 16-QAM code with PMEPR les 7.2. The code enjoys simple encoding method, has good error correction capability, and it can be decoded with a low-complexity minimum-distance (MD) algorithm

We present a framework to help the network designer to dimension optical metropolitan area networks (MAN) incorporating uncertainties in demands. In this framework the interplay among topology design, resource provisioning, and routing are analyzed jointly, based on two stochastic optimization models that use probability distributions of demands as inputs. In one model we minimize the weighted sum of network installation cost and expected penalty cost for unsatisfied traffic; in another model we minimize the network installation cost subject to certain service level requirements. The optimization results enable us: (1) to identify the physical architectures that are most robust (in cost) to demand uncertainties among rich classes of regular topologies, assuming the (random) uniform all-to-all traffic; and (2) to provide analytical references on how the optimum dimensioning, network connectivity, and network cost change as functions of the designer's level of risk aversion, service level requirements, and probability distributions of the demand.

This paper attempts to find a new analytical framework to identify cost-effective topological architectures of optical cross-connect (OXC)-switched wavelength-division multiplexing (WDM) networks. To keep the analysis tractable, we first focus on regular networks and a deterministic uniform traffic model. Regular topologies with symmetries are good approximations of metropolitan area and local area networks but only a fair resemblance of wide area networks. We find that for a regular topology the minimum-hop distance, which is normally used for gauging the size of the network, is an important parameter in dimensioning switching resources. By setting up a first-order cost model and evaluating the tradeoff between network resources, we obtain closed form solutions for the optimal node degree and network cost. For network design under stochastic traffic, we study the worst case capacity dimensioning and blocking probability among the set of all possible stochastic traffic distributions with the same mean and variance. The analytical approach presented in this paper helps us gain insights of parametric dependency of an optimal network architecture on key network design parameters.

We study the topology design of an important subset of mesh network-regular mesh network in the context of wavelength division multiplex (WDM) metropolitan area network (MAN). We find that minimum hop distance is an important parameter in dimensioning both the network's physical size but also the network node resources required to support the ever increasing traffic demand. By assigning realistic cost structures to these network nodes and link resources, we are able to specify the optimal node degrees analytically for interesting classes of good regular topologies as the networks scale in size.