BER-Adaptive RMLSA Algorithm for Wide-Area Flexible Optical Networks

Felipe Ignacio Calderon,Ariel Leiva,Gabriel Saavedra,Astrid Lozada,Ricardo Olivares,Enrique Javier Davalos,Nicolas Jara,Danilo Borquez-Paredes

doi:10.1109/access.2020.3008883

Abstract

Wide-area optical networks face significant transmission challenges due to the relentless growth of bandwidth demands experienced nowadays. Network operators must consider the relationship between modulation format and maximum reach for each connection request due to the accumulation of physical layer impairments in optical fiber links, to guarantee a minimum quality of service (QoS) and quality of transmission (QoT) to all connection requests. In this work, we present a BER-adaptive solution to solve the routing, modulation format, and spectrum assignment (RMLSA) problem for wide-area elastic optical networks. Our main goal is to maximize successful connection requests in wide-area networks while choosing modulation formats with the highest efficiency possible. Consequently, our technique uses an adaptive bit-error-rate (BER) threshold to achieve communication with the best QoT in the most efficient manner, using the strictest BER value and the modulation format with the smallest bandwidth possible. Additionally, the proposed algorithm relies on 3R regeneration devices to enable long-distances communications if transparent communication cannot be achieved. We assessed our method through simulations for various network conditions, such as the number of regenerators per node, traffic load per user, and BER threshold values. In a scenario without regenerators, the BER-Adaptive algorithm performs similarly to the most relaxed fixed BER threshold studied in blocking probability. However, it ensures a higher QoT to most of the connection requests. The proposed algorithm thrives with the use of regenerators, showing the best performance among the studied solutions, enabling long-distance communications with a high QoT and low blocking probability.

Highlights

The bandwidth demand over telecommunication networks has increased explosively over time, with average increases of approximately 30% per year [1]
Total time complexity is given by cardinality of the set BERth, K-Shortest Path, and the stage B algorithm: O(E · K · 2 · C), whose parameters are the cardinality of the set composed by the BER thresholds E, the number of paths K, the maximum number of links in a path, and the number of frequency slot units’’ (FSUs) C
TRANSLUCENT CASE In this subsection, we present the general case where several regeneration devices are deployed on the network nodes

Summary

INTRODUCTION

The bandwidth demand over telecommunication networks has increased explosively over time, with average increases of approximately 30% per year [1]. Calderón et al.: BER-Adaptive RMLSA Algorithm for Wide-Area Flexible Optical Networks transmission grid, relying on complex modulation formats, higher symbol rates, or both [4]. The main motivation is to enable long distance transmissions with a high QoT using an spectrally efficient modulation format This is achieved customizing the BER thresholds in an adaptive manner, and using one regenerator device per connection request, if necessary. For each connection request the algorithm prioritizes to reach the destination with the best BER possible, and secondly, it chooses the most efficient modulation level in terms of capacity demanded In this way, we maximize the transmission acceptance rate, while using the minimum amount of FSUs, and with the best (most strict/lowest) BER value possible. In this work we consider the case where the load is equal for all users, the so called homogeneous situation

BER-ADAPTIVE RMLSA ALGORITHM

NUMERICAL EXAMPLES

PERFORMANCE METRICS

TRANSPARENT CASE

Findings

CONCLUSION