Explore Maximal Potential Capacity of WDM Optical Networks Using Time Domain Hybrid Modulation Technique

Abstract

Abstract-The recent emerging time domain hybrid modulation (TDHM) technique is considered promising because it can realize continuous adaptation between spectral efficiency and transparent reach through appropriately allocating the time slot occupancy ratios of different modulation formats in a time-division multiplexing (TDM) frame. This technique is expected to achieve more efficient spectrum utilization or higher transmission capacity than the traditional transmission technique based on discrete modulation formats. For the point-to-point transmission system, the benefit of the TDHM technique has been experimentally verified. However, its benefit from the whole network perspective has not been explored yet. In this paper, we apply the TDHM technique to the optical network to maximize its transmission capacity. To evaluate the benefit of this technique, we consider the routing and wavelength assignment (RWA) problem for the TDHM-based WDM network, for which we develop an Integer Linear Programming (ILP) model and a waveplane-based heuristic algorithm to maximize the total network transmission capacity for the cases with and without network protection. For the protection case, the shared backup path protection (SBPP) technique is employed owing to its efficiency of spare capacity sharing and simplicity in network operation. The simulation study shows that compared to the design with discrete modulation formats, the TDHM-based approach can significantly increase the network transmission capacity. Index Terms-Time domain hybrid modulation (TDHM), rate adaptive optical network, waveplane-based heuristic algorithm, network capacityPart of the work was presented in ACP 2014 [32] and OFC 2015 [33].

Potentialities and Criticalities of Flexible-Rate Transponders in DWDM Networks: A Statistical Approach

“…To do so, optically transparent paths able to accommodate the considered LP demands are searched across the network. In our analysis, we make use of an RWA based on the waveplane method [6,7] to be fully described in Section III, but in general any RWA can be used. The RWA process terminates when the complete set of demands has been considered.…”

“…In particular, we use the incoherent GN model [11] to evaluate propagation performance and a modified waveplane method [6,7] with QoT-based routing to perform RWA. The incoherent GN model is suitable for impairment-aware networking scenarios, thanks to its independence from modulation formats and its modest computational cost.…”

“…One transponders' family is able to switch between M-QAM constellations-pure formats-delivering quantized bitrate values; the other considers the use of time-division hybrid modulation formats (TDHMFs) [4,5], enabling it to tune with continuity the bit rate, tailoring its value to the lightpath's (LP's) optical signal-to-noise ratio (OSNR). A more detailed description of these technologies can be found in [4][5][6].…”

“…This methodology starts from the waveplane-based routing and wavelength assignment (RWA) [6,7] and performs a progressive load of the network through a Monte Carlo analysis [8], in which the order according to which lightpath demands are served is varied. SNAP applies to both static and dynamic traffic models, and, in this paper, it is used for a static traffic scenario, i.e., with demands of infinite duration.…”

“…For example, using SNAP may deliver the probability for the spectrum of a link to be utilized over a certain percentage, given some traffic, RWA, topology, and physical layer characteristics. Although Monte Carlo-based algorithms for network analysis have been frequently used in the past [6,13,14], the statistical interpretation of network metrics is a novel approach, to the best of our knowledge.…”