This paper aims at providing different cost-efficient solutions for the channel impairments in tropical areas. In order to extend service to isolated areas, we propose hybrid architecture based on DVB-S2/RCS+WiFi networks. In this scenario the satellite channel is affected by deep rain events that do not allow ACM modes to protect data. Moreover, the delay in the ACM reaction to fade changes can affect the quality of the video transmission. In order to avoid the QoS reduction, we focus on different Fading Mitigation Techniques (FMT), designing a multi-layer scheme protection, using LL-FEC and AL-FEC in higher layers, and optimizing the intervention threshold and super-frame length in the physical layer. Keywords-component; DVB-S2, WiFi, LL-FEC, AL-FEC, Hybrid network, Tropical, video streaming However, since the maximum size of FEC frames is limited, and deep fading duration can be in the order of seconds, we additionally propose an Application Layer FEC solution (AL-FEC) like the one standardized for DVB-H (Handheld) and DVB-SH (DVB Satellite to Handheld), where FEC frames are allowed to be larger. Since the error protection we propose causes a noticeable delay, it cannot be used for real-time applications, which is why we focus on video streaming applications. In this paper we also demonstrate that, during the rain event, the delay in the ACM reaction to fade changes can affect the Quality of Service (QoS) of a multicast video streaming. Specifically, there is a noticeable delay (RTT of about 2 · 250ms plus DVB super-frame length) from the moment an RCS Terrestrial (RCST) detects an ongoing fade event to when it receives from the NCC the transmission with the modulation and coding rates appropriate to cope with the increased atmospheric attenuation. We verify that the LL-FEC, tuning of super-frame (SF) length and the intervention threshold are useful to compensate for the packet errors introduced by the ACM switching delay. Therefore, this work aims at demonstrating the improvement in QoS of the video transmitted in the hybrid network by using the proposed techniques and shows how to make efficient use of bandwidth in order to reduce costs in Amazon areas. The main parameters evaluated for this purpose are the packet error rate, the delay, and the bandwidth overhead due to the use of the proposed techniques. The received video will be evaluated by using the PSNR (Peak Signal to Noise Ratio) metric.
['David Pradas Fernandez', 'Lei Jiang', 'M. A. Vazquez Castro', 'Paolo Barsocchi', 'Francesco Potortì']
Cost-Efficient Design of Hybrid Network for Video Transmission in Tropical Areas