Transport layer protocols and architectures for satellite networks

Abstract

SUMMARYDesigning efficient transmission mechanisms for advanced satellite networks is a demanding task, requiring the definition and the implementation of protocols and architectures well suited to this challenging environment. In particular, transport protocols performance over satellite networks is impaired by the characteristics of the satellite radio link, specifically by the long propagation delay and the possible presence of segment losses due to physical channel errors. The level of impact on performance depends upon the link design (type of constellation, link margin, coding and modulation) and operational conditions (link obstructions, terminal mobility, weather conditions, etc.). To address these critical aspects a number of possible solutions have been presented in the literature, ranging from limited modifications of standard protocols (e.g. TCP, transmission control protocol) to completely alternative protocol and network architectures. However, despite the great number of different proposals (or perhaps also because of it), the general framework appears quite fragmented and there is a compelling need of an integration of the research competences and efforts. This is actually the intent of the transport protocols research line within the European SatNEx (Satellite Network of Excellence) project. Stemming from the authors' work on this project, this paper aims to provide the reader with an updated overview of all the possible approaches that can be pursued to overcome the limitations of current transport protocols and architectures, when applied to satellite communications. In the paper the possible solutions are classified in the following categories: optimization of TCP interactions with lower layers, TCP enhancements, performance enhancement proxies (PEP) and delay tolerant networks (DTN). Advantages and disadvantages of the different approaches, as well as their interactions, are investigated and discussed, taking into account performance improvement, complexity, and compliance to the standard semantics. From this analysis, it emerges that DTN architectures could integrate some of the most efficient solutions from the other categories, by inserting them in a new rigorous framework. These innovative architectures therefore may represent a promising solution for solving some of the important problems posed at the transport layer by satellite networks, at least in a medium-tolong-term perspective.

Satellite Space Information Network: Application and Prospect

“…When the transmission distance is less than a distance equal to the Rayleigh (Rayleigh Range), the received signal by appropriate signal processing to decode multiple independent information. Antenna spacing of 10 meters, the Rayleigh distance [9] of up to 100 kilometers. "100G radio backbone transmission network plan" recommends using a combination of various techniques to achieve performance targets.…”

A wavelength conversion scheme based on SPM and FWM for distributed satellites system with multiple wavelength channels

“…Although the principle of wavelength conversion on satellite is the same with that in optical fiber network, there are some special requirements (Ma et al 2012;Caini et al 2007) because of the limitation on payload, the low optical power and the long distance among satellites. So far, most wavelength conversion schemes need the separated pump or detecting laser, which will increase the complexity and the cost of system evidently (Baveja et al 2013;Hsieh et al 2004;Matsuura et al 2006), especially when the number of wavelengths in WDM network is larger.…”

DART: Enhancing Data Acceleration with Compression for Satellite Links

“…The inherent problems that the Adaptive Increase Multiplicative Decrease (AIMD) window based congestion control scheme used in TCP has on long delay links is related to the maximum window size, slow start phase and various time-outs. Improvements to TCP have resulted in a number of RFCs addressing this issue [1], nevertheless there is space for further improvements.…”

“…It has been shown [1] that today's most commonly used transport protocol, TCP, is not well suited to long delay links. The inherent problems that the Adaptive Increase Multiplicative Decrease (AIMD) window based congestion control scheme used in TCP has on long delay links is related to the maximum window size, slow start phase and various time-outs.…”