References of "Alagha, Nader"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailEfficient 5G Edge Caching Over Satellite
Vu, Thang Xuan UL; Maturo, Nicola UL; Vupalla, Satyaranayana et al

Scientific Conference (2018, October)

The fifth generation (5G) wireless networks have to deal with the high data rate and stringent latency requirements due to the massive invasion of connected devices and data-hungry applications. Edge ... [more ▼]

The fifth generation (5G) wireless networks have to deal with the high data rate and stringent latency requirements due to the massive invasion of connected devices and data-hungry applications. Edge caching is a promising technique to overcome these challenges by prefetching the content closer to the end users at the edge node's local storage. In this paper, we analyze the performance of edge caching 5G networks with the aid of satellite communication systems. Firstly, we investigate the satellite-aided edge caching systems in two promising use cases: a) in dense urban areas, and b) in sparsely populated regions, e.g., rural areas. Secondly, we study the effectiveness of satellite systems via the proposed satellite-aided caching algorithm, which can be used in three configurations: i) mono-beam satellite, ii) multi-beam satellite, and iii) hybrid mode. Thirdly, the proposed caching algorithm is evaluated by using both empirical Zipf-distribution data and the more realistic Movielens dataset. [less ▲]

Detailed reference viewed: 146 (9 UL)
Full Text
Peer Reviewed
See detailEnhancing mobile services with DVB-S2X superframing
Mazzali, Nicolò UL; Boumard, Sandrine; Kinnunen, Jouko et al

in International Journal of Satellite Communications and Networking (2018)

DVB-S2X is the cornerstone for satellite communication standards forming the state of the art of broadband satellite waveforms. In this paper, we propose new application scenarios and advanced techniques ... [more ▼]

DVB-S2X is the cornerstone for satellite communication standards forming the state of the art of broadband satellite waveforms. In this paper, we propose new application scenarios and advanced techniques, including a reference design implementing superframing, predistortion, a robust synchronization chain, and a plug-and-play channel interleaver. We demonstrate by means of software simulations and hardware tests that the DVB-S2X can be a common technology enabler for land-mobile, aeronautical, and maritime satellite scenarios in addition to the more traditional VSAT scenario, even in very challenging conditions (eg, very low signal-to-noise ratio). [less ▲]

Detailed reference viewed: 150 (7 UL)
See detailSymbol vs Block Level Precoding in Multi-beam Satellite Systems
Kayhan, Farbod UL; Haqiqatnejad, Alireza UL; Grotz, Joel et al

in Symbol vs Block Level Precoding in Multi-beam Satellite Systems (2018)

Precoding techniques for multi-beam satellite systems have received a considerable attention in recent years as a tool to mitigate the interference among the beams, and hence increasing the throughput ... [more ▼]

Precoding techniques for multi-beam satellite systems have received a considerable attention in recent years as a tool to mitigate the interference among the beams, and hence increasing the throughput. Our goal is to compare two main categories of precoding schemes, namely, the conventional linear block level precoding and the symbol level precoding. Focusing on power minimization problem with signal to interference plus noise ratio (SINR) constraints, symbol level precoding (SLP) has significant gains with respect to the zero forcing (ZF). However, the lower transmit power is achieved with a price: A higher computational complexity. Therefore, several sub-optimal SLP techniques have been proposed in the literature to overcome the complexity. While ZF has the lowest complexity among the techniques chosen in this paper, it is not an optimal linear block level precoder as far as power minimization is concerned. Therefore, in order to have a more complete picture, one needs also to consider optimal block level precoders. Our results indicate that in order to have a fair comparison, one needs to consider two different scenarios, namely, low and high SINR threshold regimes. While for low SINRs the optimal linear block level precoding scheme may provide a good solution with reasonable complexity, for high SINR threshold, the SLP techniques become more attractive. Our results also indicate that the performance of SLP highly depends on the chosen constellation space, and therefore a final conclusion can be achieved only after appropriately optimizing the constellation set. [less ▲]

Detailed reference viewed: 137 (27 UL)
Full Text
See detailOptimized non-orthogonal multiplexing in Peak Power Limited Channels
Alagha, Nader; Kayhan, Farbod UL; Montorsi, Guido

Scientific Conference (2017, October)

In this paper, we investigate the performance of optimized overlay modulation schemes and compare the results with both time division multiplexing and superposition modulation assuming a peak power ... [more ▼]

In this paper, we investigate the performance of optimized overlay modulation schemes and compare the results with both time division multiplexing and superposition modulation assuming a peak power limited AWGN channel. We show that significant gains can be achieved by properly designing the constellation set, specially in the presence of large SNIR imbalance between the user's link quality. We introduce two realistic case studies and present the results for each scenario. [less ▲]

Detailed reference viewed: 125 (5 UL)
Full Text
Peer Reviewed
See detailComparative Assessment of Orthogonal and Nonorthogonal Multiplexing Techniques for Differentiated Satellite Broadcasting Services
Kayhan, Farbod UL; Montorsi, Guido; Taricco, Giorgio et al

Scientific Conference (2015)

This paper presents a comparative assessment of two multiplexing techniques for providing differentiated classes of services over a realistic broadcasting satellite channel under variable link conditions ... [more ▼]

This paper presents a comparative assessment of two multiplexing techniques for providing differentiated classes of services over a realistic broadcasting satellite channel under variable link conditions. A distinctive characteristic of satellite broadcasting channels is the non-linear characteristics of high power amplifier on-board of the satellite. In this scenario, the conventional additive white Gaussian noise (AWGN) channel with average power limitation is no longer an accurate model and nonlinear characteristics have to be taken into account. Orthogonal multiplexing (time sharing) techniques combined with variable coding and modulation are compared with hierarchical modulations with the goal of maximizing the number of broadcast channels over a given transponder while maintaining a target service availability. Hierarchical modulations are shown to provide better performance than orthogonal time division multiplexing (time-sharing) schemes for the AWGN channel. Here we design a practical transmitter scheme based on the hierarchical modulation and maximize the throughput by optimizing the achievable mutual information for finite size constellations. This will provide a lower bound on throughput which can be achieved by non orthogonal multiplexing scheme. We compare the performance of hierarchical modulation (non-orthogonal multiplexing) and time sharing techniques (orthogonal multiplexing) supporting two different service quality and service availability requirements for broadcasting the same content. [less ▲]

Detailed reference viewed: 198 (12 UL)
Full Text
Peer Reviewed
See detailPushing for higher rates and efficiency in Satcom: the different perspectives within SatNExIV
Vazquez, Miguel-Angel; Neira, Ana-Perez; Mosquera, Carlos et al

in Proceedings of the 11th International Symposium on Wireless Communication Systems (ISWCS 2015) (2015)

SatNEx IV project aims at studying medium and long term directions of satellite telecommunication systems for any of the commercial or institutional applications that can be considered appealing by key ... [more ▼]

SatNEx IV project aims at studying medium and long term directions of satellite telecommunication systems for any of the commercial or institutional applications that can be considered appealing by key players although still not mature enough for attracting industry or initiating dedicated ESA R&D activities. This paper summarizes the first year activities identified as very promising techniques for next generation satellite communication systems. Concretely, very high throughput satellite trunking, physical layer advances for fullduplex and multipolarization systems, network coding applications and multiple access schemes for information centric networking are briefly presented. For all the activities, we identify the scenarios under study so as the preliminary technical solutions to be further investigated. [less ▲]

Detailed reference viewed: 158 (4 UL)