Asynchronous multi-class traffic management in wide area networks

The emergence of new applications brings multi-class traffic with diverse quality of service (QoS) requirements to wide area networks (WANs), motivating research in traffic engineering (TE). In recent years, novel centralized and hierarchical TE schemes have used heuristic or machine learning techniques to orchestrate resources in closed systems such as datacenter networks. However, these schemes suffer from long delivery delays and high control overhead when applied to general WANs. To provide low-delay services, this paper proposes an asynchronous multi-class traffic management (AMTM) scheme. We first establish an asynchronous TE paradigm in which distributed nodes locally perform low-complexity and low-delay traffic control based on link prices, and the TE server updates link prices to eliminate decision conflicts between edge nodes. By modeling the asynchronous TE paradigm as a control system with non-negligible control loop delay, we find that the traditional pricing strategy cannot simultaneously achieve a low packet loss rate and a low flow delivery delay. To address this issue, we propose a new pricing strategy based on the observations of virtual queues in intermediate nodes. We also present a system design and related algorithms that utilize a dynamic step size mechanism of link price update. Simulation results show that AMTM can effectively reduce the end-to-end flow delivery delay

Smart Communication Satellite (SCS) Project Overview

Smart Communication Satellite (SCS) is the first low earth orbit (LEO) mobile communication test satellite of China, whose core mission is to conduct technical exploration and verification for building satellite internet. Launched in September, 2014, SCS completed its whole on-orbit experiments in October, 2014. In order to resolve the contradiction between the coverage area and communication rate of LEO communication satellites, SCS adopts on- board smart antenna, whereby dynamically changing spot beams can be formed. Moreover, SCS has developed payload-centered satellite design technique as well as internet-oriented software satellite technique, and finally accomplished the design for application-oriented micro-satellite which is 100Kg-class weighted and applicable to communication and navigation services. The innovative techniques of SCS verify the new direction of development in the future satellite internet

Guest Editorial: Space Information Networks: Technological Challenges, Design Issues, and Solutions

It has been expected that the space information networks (SIN), as an extension of the terrestrial network, would provide high-speed, high-capacity, global continuous communication, and data transmission services anywhere for anyone at any time. With rapid advances in relevant technologies (e.g., satellite miniaturization technology, reusable rocket launch technology, and semiconductor technology), low-orbit satellites, drones, and airships can be integrated into the SIN to supply more comprehensive network connectivity. The standard development organizations including 3GPP, ITU, and ETSI already starts corresponding standardization activities to support nonterrestrial networks in SIN. It can be foreseen that SIN will be expanded to provide not only telephone services but also various kinds of Internet services, and it is thus able to serve many more users with different demands