Advanced Fade Countermeasures for DVB-S2 Systems in Railway Scenarios

Abstract

This paper deals with the analysis of advanced fade countermeasures for supporting DVB-S2 reception by mobile terminals mounted on high-speed trains. Recent market studies indicate this as a potential profitable market for satellite communications, provided that integration with wireless terrestrial networks can be implemented to bridge the satellite connectivity inside railway tunnels and large train stations. In turn, the satellite can typically offer the coverage of around 80% of the railway path with existing space infrastructure. This piece of work, representing the first step of a wider study, is focusing on the modifications which may be required in the DVB-S2 standard (to be employed in the forward link) in order to achieve reliable reception in a challenging environment such as the railway one. Modifications have been devised trying to minimize the impact on the existing air interface, standardized for fixed terminals.

Propagation Impairment Countermeasures in Mobile Stratospheric Operating Environment

“…Following the analysis of channel traces and respecting the considered QoS framework, the aim of this section is to discuss the suitability of numerous propagation impairment countermeasures in the mobile access segment of HAP-based communication system. Before discussing some of the promising techniques [11,12,13] or their combinations more in detail, a perspective of their usage and optimization should be stated. From the link perspective the propagation impairment countermeasures may be pre-estimated, i.e.…”

Code Acquisition for Next Generation Mobile Broadband Satellite Services

“…CHANNEL MODEL According to propagation measurements and the DVB-RCS+M framework analysis, aeronautical and maritime propagation condition can be safely modeled through the classical AWGN channel [2]. For the railway scenario, rigorous modeling for the Line of Sight (LoS) propagation conditions calls for a Rice fading channel with a Rice factor of K = 17.5 dB, with superposition of a square wave 0 or 1 with duty cycle 1% that models the periodic obscuration events induced by the equally spaced electrical trellises (also referred to as power arches) used on the railway [2] to supply power to the electrical trains. According to this model, the channel is "on" with Rice propagation for 99% of the time, while it is "off" for the residual 1%, the transition from on to off occurring periodically.…”

“…In 2006 the Digital Video Broadcasting -Technical Module (DVB-TM) approved a new study mission aimed at extending the capabilities of the DVB-RCS (Return Channel via Satellite) standard to support broadband services to mobile collective terminals in aeronautical, maritime, and railway land mobile scenarios 1 [1] [2]. The new standard is expected to be finalized by early 2008 and will be identified as DVB-RCS+M.…”

“…In this paper, we report the original results of the design and performance assessment of the code synchronization subsystem that have been carried out by the authors in support of the adoption of DS-SS by the DVB-RCS+M ad-hoc group. The design described in the paper refers in particular to the DVB-RCS+M forward link (FL) in the most challenging railway scenario [2], characterized by periodic blockages and spreading factors up to 4. Code synchronization is accomplished jointly with frame acquisition in order to limit the impact on the receiver architecture.…”

Opportunistic Multicast Scheduling with Erasure-Correction Coding over Wireless Channels

“…A similar packet-level coding structure used for a different purpose has been proposed for DVB-S2, e.g., see[13].…”