Impact of Scheduling in the Return-Link of Multi-Beam Satellite MIMO Systems

The utilization of universal frequency reuse in multi-beam satellite systems introduces a non-negligible level of co-channel interference (CCI), which in turn penalizes the quality of service experienced by users. Taking this as starting point, the paper focuses on resource management performed by the gateway (hub) on the return-link, with particular emphasis on a scheduling algorithm based on bipartite graph approach. The study gives important insights into the achievable per-user rate and the role played by the number of users and spot beams considered for scheduling. More interestingly, it is shown that a free-slot assignment strategy helps to exploit the available satellite resources, thus guaranteeing a max-min rate requirement to users. Remarks about the trade-off between efficiency-loss and performance increase are finally drawn at the end of the paper.Comment: Submitted and accepted to IEEE GLOBECOM 2012 Conference, 6 pages, 10 figure

Transport Protocol for Future Aeronautics

Space scienc

Rapidly deployable satellite communications for emergency situations: the WISECOM trials

This paper presents a general overview of the WISECOM (Wireless Infrastructure over Satellite for Emergency Communications) system, focusing on the trials performed on a specifically developed demonstrator during a live simulation of a disaster event. The WISECOM system is intended to rapidly deploy a complete communications infrastructure in the early hours after a disaster occurs through the integration of several terrestrial networks, such as GSM, WiFi, WiMAX and TETRA, with satellite systems, such as Inmarsat BGAN and DVB-RCS. In order to test the fulfilment of the different capabilities that are required by the system, a demonstrator has been designed, implemented and finally used in a simulation scenario. The architecture of the developed demonstrator is described introducing two versions of the system intended to be used in the different phases after the disaster event. The work details the different capabilities tested on the WISECOM demonstrator, before and during the live simulation, taking into account the drawbacks of already existing solutions for communication in emergency scenarios and analysing the achieved improvements. The main aim of the system is to provide victims and members of rescue forces with voice and data services, such as transmission of images and Location Based Services, in order to improve the coordination of rescue operations and reduce the necessary time until victims receive a proper treatment

BSM Integrated PEP with Cross-Layer Improvements

Abstract-The future development of broadband satellite systems providing services based on the Internet Protocol (IP) needs to be stimulated by means of common standards. This paper presents the ETSI BSM PEP terminal architecture and PEP usage scenarios. In addition this paper shows the benefits of cross-layer improvements, where the TCP traffic sent by STs through an NCC/Gateway that acts as a PEP-spoofer on ACKs going in the opposite direction

Subset Optimization of Adaptive Coding and Modulation Schemes for Broadband Satellite Systems

The number of Coding and Modulation Schemes suggested for the two standards DVB-S2 and DVB-RCS (in its "advanced" version) is clearly overdimensioned; a subset of schemes can be used by reducing the overall system performance negligibly. This paper presents the investigations performed on this rain fading mitigation technique, called Adaptive Coding and Modulation (ACM), supported by the DVB-S2 standard and shows how the sets of modulation and coding schemes, considered in the forward- and in the return-links, can be changed to reduce terminal complexity and how this affects the overall system performance. It is shown that, by a careful selection of the ACM schemes, already with less than one fourth (7 or 5 out of 28) of the total number of schemes it is possible to get performance close to the optimum, but with a much lower terminal complexity

On the Behavior of RObust Header Compression U-mode in Channels with Memory

The existing studies of RObust Header Compression (ROHC) have provided some understanding for memoryless channel, but the behavior of ROHC for correlated wireless channels is not well investigated in spite of its practical importance. In this paper, the dependence of ROHC against its design parameters for the Gilbert Elliot channel is studied by means of three analytical models. A first more elaborated approach accurately predicts the behavior of the protocol for the single RTP flow profile, while a simpler, analytically tractable model yields clear and insightful mathematical relationships that explain the qualitative trends of ROHC. The results are validated against a real world implementation of this protocol. Moreover, a third model studies also the less conventional yet practically relevant setting of multiple RTP flows

Interworking between Performance Enhancing Proxies and Broadband Satellite Multimedia (BSM) security architecture

Satellites had been successful in the past due to their wide area coverage and speedy deployment of new services especially in remote regions of Europe and the rest of the world. The future development of broadband satellite systems providing services based on the Internet Protocol (IP) needs to be stimulated by means of common standards. This paper presents the ETSI BSM PEP terminal architecture, PEP usage scenarios and security configurations for successful PEP implementations

On the Achievable Rates for the Return-Link of Multi-Beam Satellite Systems Using Successive Interference Cancellation

This paper investigates the theoretically reachable rates in the return-link of multi-user multi-beam satellite systems. The return-link can actually be analyzed by means of multiple-input multiple-output signal processing techniques. While MIMO inspired multi-user detection for the return-link of satellite systems has been partly investigated in the past, a fundamental look at the achievable gains by these advanced signal processing techniques for satellite communications is missing. Depending on the number of colors used in the system, the available bandwidth per beam can be traded off against the level of co-channel interference. This paper explores the fundamental limits dictated by information theory to the communication rates on satellite multi-beam scenarios, and the impact of a realistic beam patterns on these data rates