Satellite Communications

This study is motivated by the need to give the reader a broad view of the developments, key concepts, and technologies related to information society evolution, with a focus on the wireless communications and geoinformation technologies and their role in the environment. Giving perspective, it aims at assisting people active in the industry, the public sector, and Earth science fields as well, by providing a base for their continued work and thinking

ATS-6 engineering performance report. Volume 5: Propagation experiments

Propagation experiments at 1550 MHz to 1650 MHz are reviewed, including the Integrated L-Band Experiments system and results, and the Mobile L-Band Terminals for Satellite Communication system. Experiments at 4 GHz to 6 GHz are reported, including the Radio Frequency Interferometer Measurements system and results, and Earth station antenna evaluations. Experiments above 10 GHz are discussed, including Comsat and ATS-6 millimeter wave propagation/experiments, and communication ATS-6 version at 20 and 30 GHz

Proceedings of the Second International Mobile Satellite Conference (IMSC 1990)

Presented here are the proceedings of the Second International Mobile Satellite Conference (IMSC), held June 17-20, 1990 in Ottawa, Canada. Topics covered include future mobile satellite communications concepts, aeronautical applications, modulation and coding, propagation and experimental systems, mobile terminal equipment, network architecture and control, regulatory and policy considerations, vehicle antennas, and speech compression

Proceedings of the Fifth International Mobile Satellite Conference 1997

Satellite-based mobile communications systems provide voice and data communications to users over a vast geographic area. The users may communicate via mobile or hand-held terminals, which may also provide access to terrestrial communications services. While previous International Mobile Satellite Conferences have concentrated on technical advances and the increasing worldwide commercial activities, this conference focuses on the next generation of mobile satellite services. The approximately 80 papers included here cover sessions in the following areas: networking and protocols; code division multiple access technologies; demand, economics and technology issues; current and planned systems; propagation; terminal technology; modulation and coding advances; spacecraft technology; advanced systems; and applications and experiments

Novel Estimation and Detection Techniques for 5G Networks

The thesis presents several detection and estimation techniques that can be incorporated into the fifth-generation (5G) networks. First, the thesis presents a novel system for orthogonal frequency division multiplexing (OFDM) to estimate the channel blindly. The system is based on modulating particular pairs of subcarriers using amplitude shift keying (ASK) and phase-shift keying (PSK) adjacent in the frequency domain, which enables the realization of a decision-directed (DD) one-shot blind channel estimator (OSBCE). The performance of the proposed estimator is evaluated in terms of the mean squared error (MSE), where an accurate analytical expression is derived and verified using Monte Carlo simulation under various channel conditions. The system has also extended to exploits the channel correlation over consecutive OFDM symbols to estimate the channel parameters blindly. Furthermore, a reliable and accurate approach has been introduced to evaluate the spectral efficiency of various communications systems. The metric takes into consideration the system dynamics, QoS requirements, and design constraints. Next, a novel efficient receiver design for wireless communication systems that incorporate OFDM transmission has been proposed. The proposed receiver does not require channel estimation or equalization to perform coherent data detection. Instead, channel estimation, equalization, and data detection are combined into a single operation, and hence, the detector performs a direct data detector (D3). The performance of the proposed D3 is thoroughly analyzed theoretically in terms of bit error rate (BER), where closed-form accurate approximations are derived for several cases of interest, and validated by Monte Carlo simulations. The computational complexity of D3 depends on the length of the sequence to be detected. Nevertheless, a significant complexity reduction can be achieved using the Viterbi algorithm (VA). Finally, the thesis proposes a low-complexity algorithm for detecting anomalies in industrial steelmaking furnaces operation. The algorithm utilizes the vibration measurements collected from several built-in sensors to compute the temporal correlation using the autocorrelation function (ACF). Furthermore, the proposed model parameters are tuned by solving multi-objective optimization using a genetic algorithm (GA). The proposed algorithm is tested using a practical dataset provided by an industrial steelmaking plant

TRANSPORT PROTOCOL AND FLOW CONTROL FOR IP-BASED BROADBAND AERONAUTICAL SATELLITE NETWORKS

The IP-based broadband aeronautical satellite network will provide numerous new applications and services for both airspace system operations and passenger communications. However, the interoperation between a satellite system and the exiting terrestrial Internet infrastructure introduces new challenges. In this thesis, we recommend suitable transport protocols for an aeronautical network supporting Internet and data services via satellite. We study the future IP-based aeronautical satellite hybrid network and focus on the problems that cause dramatically degraded performance of the Transport Protocol. Based on the observation that it is difficult for an end-to-end TCP solution to solve the performance problem effectively, we proposed a new splitting based transport protocol, called Aeronautical Transport Control Protocol (AeroTCP). The main idea of AeroTCP is the fixed window flow control, adaptive congestion control, and super fast error control. Simulation results showed that AeroTCP can achieve high utilization of satellite channel and fairness

Cross-layer energy efficiency of plc systems for smart grid applications

Though opinions are still divided over the specific choices of technology for smart grid, there is a consensus that heterogeneous communications network is most appropriate. Power line communication (PLC) is promising because it is readily available and it aligns with the natural topology of power distribution network. One of the emerging realities is that the communication system enabling smart grid must be energy-efficient. This thesis employs a cross-layer approach to address energy efficiency of PLC networks in different smart grid scenarios. At network layer, this work exploits the topology of a PLC-enabled advanced metering infrastructure (AMI) to improve the probability of successful packet delivery across the network. The technique, termed AMI clustering, leverages the traditional structure of the low voltage (LV) network by organising the smart meters into clusters and locally aggregating their readings. Improvement in packet delivery inherently reduces energy wastage. Next, the adaptation layer exploits the low data rate transmission techniques to reduce the energy requirements of PLC nodes. To achieve that, this work developed a network model in NS-3 (an open-source network simulator) that considers PLC transceivers as resource-constrained devices and interconnects them to emulate home energy management system (HEMS). The model was validated with experimental results which showed that in the home area network (HAN), low-rate applications such as energy management can be supported over low-power PLC networks. Furthermore, at physical layer, this thesis proposes a more energy-efficient multi-carrier modulation scheme than the orthogonal frequency division multiplexing (OFDM) used in most of the current PLC systems. OFDM is widely known for its high peak-to-average-power ratio (PAPR) which degrades energy efficiency of the systems. This thesis found that by employing vector- OFDM (V-OFDM), power requirements of PLC transmitter can be reduced. The results also showed the energy efficiency can be further improved by using a dynamic noise cancellation technique such as dynamic peak-based threshold estimation (DPTE) at the receiver. By applying the proposed methods, packet delivery can be improved by 3% at network layer (which conserves energy) and reduced data rate can save about 2.6014 dB in transmit power. Finally, at physical layer, V-OFDM and DPTE can respectively provide 5.8 dB and 2.1 dB reduction in power requirements of the PLC transceivers. These signify that if V-OFDM is combined with DPTE, future PLC modems could benefit from energy-efficient power amplifiers at reduced cost