Network Coding Strategies for Satellite Communications

Network coding (NC) is an important technology that allows the network services to be optimal. The main advantage of NC is to reduce the necessity for re-transmissions of packets. Satellite Communications (SatComs) are one of the potential applications that can leverage on the benefits of NC due to their challenging fading environments and high round trip times. The motivation is to take the physical layer-awareness into consideration for adapting and hence extend the NC gains. Different rate and energy efficient adaptive NC schemes for time variant channels are proposed. We compare our proposed physical layer adaptive schemes to physical layer non-adaptive NC schemes for time variant channels. The adaptation of packet transmissions is on the basis of the corresponding time-dependent erasures, and allows proposed schemes to achieve significant gains in terms of throughput, delay and energy efficiency. The proposed schemes are robust for large and small size of packets. Although, the energy per bit is affected, a similar rate and energy gains can be arise. However, the performance gains are not motivated by the packet size, but through duty cycle silence of transfer packets. In this thesis, virtual schemes are also proposed to solve an open literature problem in the NC. The objective is to find a quasi-optimal number of coded packets to multicast to a group of independent wireless receivers suffer from a different channel conditions. In particular, we propose two virtual network that allows for the representation of a group of receivers as a multicast group to be visible as one receiver and single channel. Most of the schemes are applied to LEO/MEO/GEO satellite scenarios. They demonstrate remarkable gains compared to that strategy in which the adaptation depends only on one receiver point-to-point

Energy Efficient Adaptive Network Coding Schemes for Satellite Communications

In this paper, we propose novel energy efficient adaptive network coding and modulation schemes for time variant channels. We evaluate such schemes under a realistic channel model for open area environments and Geostationary Earth Orbit (GEO) satellites. Compared to non-adaptive network coding and adaptive rate efficient network-coded schemes for time variant channels, we show that our proposed schemes, through physical layer awareness can be designed to transmit only if a target quality of service (QoS) is achieved. As a result, such schemes can provide remarkable energy savings.Comment: Lecture Notes of the Institute for Computer Sciences, Social Informatics and Telecommunications Engineering, 24 March 201

Adaptive Network Coding Schemes for Satellite Communications

In this paper, we propose two novel physical layer aware adaptive network coding and coded modulation schemes for time variant channels. The proposed schemes have been applied to different satellite communications scenarios with different Round Trip Times (RTT). Compared to adaptive network coding, and classical non-adaptive network coding schemes for time variant channels, as benchmarks, the proposed schemes demonstrate that adaptation of packet transmission based on the channel variation and corresponding erasures allows for significant gains in terms of throughput, delay and energy efficiency. We shed light on the trade-off between energy efficiency and delay-throughput gains, demonstrating that conservative adaptive approaches that favors less transmission under high erasures, might cause higher delay and less throughput gains in comparison to non-conservative approaches that favor more transmission to account for high erasures.Comment: IEEE Advanced Satellite Multimedia Systems Conference and the 14th Signal Processing for Space Communications Workshop (ASMS/SPSC), 201

Network Coding Channel Virtualization Schemes for Satellite Multicast Communications

In this paper, we propose two novel schemes to solve the problem of finding a quasi-optimal number of coded packets to multicast to a set of independent wireless receivers suffering different channel conditions. In particular, we propose two network channel virtualization schemes that allow for representing the set of intended receivers in a multicast group to be virtualized as one receiver. Such approach allows for a transmission scheme not only adapted to per-receiver channel variation over time, but to the network-virtualized channel representing all receivers in the multicast group. The first scheme capitalizes on a maximum erasure criterion introduced via the creation of a virtual worst per receiver per slot reference channel of the network. The second scheme capitalizes on a maximum completion time criterion by the use of the worst performing receiver channel as a virtual reference to the network. We apply such schemes to a GEO satellite scenario. We demonstrate the benefits of the proposed schemes comparing them to a per-receiver point-to-point adaptive strategy

Physical layer aware adaptive network coding schemes for satellite communications

Network coding is a technology that provides core benefits to communication services, in terms of reliability, latency, and data rate, by leveraging on a coding structure that reduces the necessity for retransmissions of packets. Satellite communications are one of the potential applications that can leverage on the benefits of network coding due to their challenging fading environments and high round trip times. By introducing physical layer awareness, network coding offers further gains to such communications systems. In this paper, we propose different rate and energy efficient adaptive network coding schemes for time-variant channels. We compare our proposed physical layer aware adaptive schemes to physical layer nonadaptive network coding schemes for time-variant channels. The proposed schemes demonstrate that adaptation of packet transmissions based on the channel variations over time, and their corresponding time-dependent erasures, allows for significant gains in terms of throughput, delay, and energy efficiency. We shed light on the trade-off between energy efficiency and delay-throughput gains, demonstrating that conservative adaptive approaches that favor less transmission under high erasures might cause higher delay and less-throughput gains in comparison to nonconservative approaches that favor more transmissions to account for high erasures. We show that such schemes are robust with regimes of large or small packet sizes; albeit the energy per bit is affected, similar rate and energy gains can be obtained. In turn, we show that the performance gains are driven by the duty cycle of the packets silent transmission and not by the packet size