Motivation for this work is the development of a new satellite air interface for a low data rate massive access network in the context of machine-to-machine communications (M2M)/Internet of things (IoT) applications. For this purpose, this chapter considers energy efficiency at the user terminal and gives an evaluation of hardware-related aspects for an energy-efficient air interface and introduces a hardware concept involving energy harvesting in combination with an intelligent energy and system management. Typically, the performance of air interfaces is measured in terms of throughput, transmit error performances, etc. However, we evaluate for energy efficiency, an additional hardware-related aspect, which indicates the joint energy efficiency of hardware and transmission scheme. In particular, conventional continuous transmission of a message is opposed to discontinuous transmission by telegram splitting, as specified for the telegram splitting ultra-narrowband (TS-UNB) technology standardized by European Telecommunications Standards Institute (ETSI). Evaluations show that discontinuous transmission exploits the hardware components in a more efficient way than continuous transmission. This results in an extended use of the battery, which translates into a longer lifetime of the user node.

Advance satellite communications technology has been achieved through Wideband InterNetworking engineering test Satellite (WINDS) and Engineering Test Satellite 9 (ETS-IX) projects in these two decades in Japan. WINDS achieved Gbps-class transmission capability, wide bandwidth active phased array antenna in Ka-band, and high speed onboard switching technologies. ETS-IX is currently being developed to demonstrate flexible resource management capability with wide bandwidth digital channelizer and digital beam former in Ka-band. In this chapter, very high capacity optical communications technology being developed for feeder link applications of a very high throughput satellite is reviewed. Satellite communications are thought to be beneficial for 5G coverage expansion to the ocean surface, air and space, and some trials to integrate to 5G. ETS-IX will be used as an experimental platform for such technical trials based on European Space Agency-National Institute of Information and Communications Technology (ESA-NICT) collaborations. Based on these achievements and experiences, and taking into account the recent trend of satellite communications technology for VHTS, LEO constellations, HAPS, and so on, we have studied next-generation satellite communications technology.

The International Communications Satellite Systems Conference (ICSSC) is the oldest and one of the most influential technical conferences in the field. The 37th edition was held from 29 Oct - 1 Nov 2019 in Okinawa, Japan. These proceedings present a broad spectrum of space communications contributions from the conference, with highlights including high speed optical communications and feeder links, advanced digital payloads, broadband satellite communication architectures and applications. Subjects covered include integrated applications and architectures for vessels and IoT; DTN and HTS technologies; new satellite system architectures and components; high speed optical communications and feeder links; advanced digital payloads and components; satellite antenna technologies; propagation and modelling for satellite communications; future technologies for 5G and beyond; flexible HTS systems and advanced digital payloads; satellite networks design challenges and applications; new satellite components and transmitter and modem technologies; NGSO constellations and 5G integration; and NGSO and GSO system issues and interference mitigation techniques. Offering a wide range of expert perspectives on communications satellite systems, these proceedings will be of interest to engineers and researchers in academia and industry working on satellite, digital, and wireless communications and networks, as well as advanced students, policy makers and stakeholders in the field.

The Wideband InterNetworking engineering test and Demonstration Satellite (WINDS) was developed for the research of high-data-rate satellite communication technologies using Ka-band. WINDS was launched on February 23, 2008 and completed its operation on February 27, 2019. The National Institute of Information and Communications Technology (NICT) planned and conducted various experiments, such as satellite communication experiments for disaster countermeasures, an orthogonal frequency-division multiplexing transmission experiment, and mobile satellite communication experiments, using a small vehicle earth station, an airborne earth station, and a seaborne earth station.

The growing complexity of spacecraft constellations, communication relay offerings, and mission architectures drives the need for the development of autonomous communication systems. The National Aeronautics and Space Administration (NASA) has traditionally launched single spacecraft missions that are served by the Space Communication and Navigation (SCaN) program. Operations on SCaN networks are typically scheduled weeks in advance, and often each asset serves a single user spacecraft at a time. Recent movement towards swarm missions could make the current approach unsustainable. Additionally, the integration of commercial communication service providers will substantially increase the data transfer options available to new missions. NASA science missions have found benefit in launching swarms of space-craft, allowing coordinated simultaneous observations from different perspectives. Inter-spacecraft communication (mesh networking) is an enabler for this architecture, as are CubeSats that allow cost-effective provisioning of distributed mission assets. As more complex swarm missions launch, one challenge is coordinating communication within the swarm and choosing the appropriate mechanism for telemetry, tracking, control, and data services to and from Earth. Cognitive communications research conducted by SCaN aims to mitigate the increasing communication complexity for mission users by increasing the autonomy of links, networks, and service scheduling. By considering automation techniques including recent advances in artificial intelligence and machine learning, cognitive algorithms and related approaches enable increased mission science return, improved resource utilization for service provider networks, and resiliency in unpredictable or unplanned environments. The Cognitive Communications Project at the NASA Glenn Research Center develops applications of data-driven, nondeterministic methods to improve the autonomy of space communication. The project emphasizes the development of decentralized space networks with artificial intelligence agents optimizing communication link throughput, data routing, and system-wide asset management. This chapter discusses the objectives, approaches, and opportunities of the research to address growing needs of the space communications community.

In this study, a novel predictive event-triggered load frequency control has been developed for a hybrid power system with renewable energy sources (RESs) to deal with denial-of-service (DoS) attacks, where the DoS duration (the time attack lasts) are boundless. A predictive event-triggered transmission scheme is built for the multi-area hybrid power systems under DoS attacks to reduce the load of network bandwidth while maintaining adequate levels of performance. Therefore, an observer-based predictive controller is developed in the presence of both external disturbances and DoS attacks by formulating the LFC problem as a disturbance attenuation issue. In the proposed method, a hybrid power system with RESs is used to achieve novel and better security strategies. Based on the new model, sufficient conditions are obtained using the Lyapunov stability theory to ensure a stable multi-area hybrid power system with a prescribed performance. Moreover, an algorithm is provided to obtain the control strategy of DoS attacks. Finally, the simulation of a hybrid power system with RESs is presented to demonstrate the effectiveness of the proposed method in dealing with the DoS attacks.

Comparing with the cloud computing, mobile edge computing (MEC) can further decrease the latency and improve the stability of the networks. However, it is challenging for the edge servers to deal with the large computation task due to the limited computing capacity. In this study, we design a novel three-layer network architecture consisting of mobile devices, edge cloudlets, and helper cloudlets, where the computing data can be partially processed at the edge cloudlet and helper cloudlet. Based on this, a joint communication, offloading, and computation resource allocation problem is formulated to minimise the computation cost and energy consumption. Due to its difficulty to directly solve the formulated problem, we first propose an offloading scheme to obtain the closed-form solutions for the optimal offloading data size. Next, we decompose the optimisation problem into two subproblems: (i) for the cloud execution, we dynamically adjust the data transmission rate according to the stochastic channel condition, (ii) for the mobile execution, the energy consumption can be further reduced by applying the dynamic voltage and frequency scaling technique. Finally, the numerical results demonstrate the efficiency of the proposed scheme, and show the performance gains in terms of delay, computation cost and energy consumption.

This study presents the design analysis and correlation properties of a new spreading code for the incoherent synchronous pulse position modulation-optical code division multiple access (PPM-OCDMA) networks. The proposed code called optimised modified prime code (OMPC), which refers to the modified prime codes (MPCs) family. Additionally, this new code designed at a higher code length, optimised code weight and good correlation characteristics to enhance communication security and improve the bit error rate (BER) performance. In this study, the proposed code is used as source code for different kinds of multimedia services such as data, voice, and video. Furthermore, the characteristics and correlation properties of the OMPC in comparison with the other MPCs families that utilised in the PPM-OCDMA networks are presented. Moreover, for the PPM-OCDMA networks, the effect of OMPC auto- and cross-correlation properties on the multiple access interference (MAI) was investigated. Consequently, the MAI is considered in the BER analysis and calculations. Finally, the results show that the proposed OMPC is better than the other existing codes with respect to the channel capacity and system performance.

Mobile edge computing (MEC) is concerned with moving complex tasks from data sources to nearby computing resources, which can reduce computing latency and remote cloud workload. Although there has been significant research in the field of MEC, research on edge server placement in wireless metropolitan area networks (WMANs) is overlooked, and the load balancing problem of edge servers is seldom discussed. From a practical perspective, how to place edge servers efficiently in WMANs while considering load balancing between edge servers is studied. A greedy algorithm is proposed that can balance the workload of edge servers more effectively. However, the performance of the greedy algorithm as the number of servers placed increases is not ideal. Therefore, the authors combine the greedy algorithm with a genetic algorithm (GA) to minimise the number of edge servers while ensuring load balancing between edge servers and quality of service (QoS) requirements for mobile users. Finally, they conduct simulation experiments and compare the proposed algorithms with other algorithms. The improved GA proposed is superior to the greedy algorithm in terms of load balancing and the number of servers. The experimental results demonstrate that the algorithm has excellent performance.

Fast session transfer (FST) is introduced by wireless gigabit (WiGig) standards to transfer the data communication session among wireless fidelity (Wi-Fi) and WiGig channels based on the availability. In the conventional Wi-Fi/WiGig FST decision-making, the session of data transmission is transferred from Wi-Fi to WiGig whenever it is possible regardless of the traffic loads on both bands and the expected WiGig blocking probability. Also, WiGig to Wi-Fi FST occurs whenever the WiGig signal is lost even if the WiGig link is undergoing an instant path blocking. This results in Wi-Fi/WiGig load imbalance as well as large average delay in user data delivery. In this study, a novel Wi-Fi/WiGig FST decision-making algorithm is proposed utilising fuzzy logic while considering the coverage probability of the WiGig link, the sizes of the users' remaining messages relative to the available data rates of both bands, and the probability of WiGig path blocking. Furthermore, a WiGig interruption-classification methodology is proposed to detect the occurrence of the WiGig instant path blocking and then decide if it is better to wait for WiGig signal recovery or immediately transfer to Wi-Fi. Simulation analysis demonstrates the effectiveness of the proposed Wi-Fi/WiGig FST decision-making algorithm, over the conventional one.