scholarly journals Dynamic Divide Grouping Non-Orthogonal Multiple Access in Terrestrial-Satellite Integrated Network

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6199
Author(s):  
Yanjun Yan ◽  
Huihui Xu ◽  
Ning Zhang ◽  
Guangjie Han ◽  
Mingliu Liu
Keyword(s):  
Multiple Access ◽  
Elevation Angle ◽  
Base Station ◽  
Satellite Networks ◽  
Control Factor ◽  
Satellite Network ◽  
Total System ◽  
Integrated Network ◽  
User Pairing ◽  
Terrestrial Networks

Non-orthogonal multiple access (NOMA) has been extensively studied to improve the performance of the Terrestrial-Satellite Integrated Network (TSIN) on account of the shortage of frequency band resources. In this paper, the terrestrial network and satellite network synergistically provide complete coverage for ground users, and based on the architecture, we first formulate a constrained optimization problem to maximize the sum rate of the TSIN under the limited spectrum resources. As the terrestrial networks and the satellite network will cause interference to each other, we first investigate the capacity performance of the terrestrial networks and the satellite networks separately, in which the optimal power control factor expression is derived. Then, by constructing the relationship model between user elevation angle, beam angle and distance, we develop a dynamic group pairing schemes to ensure the effective pairing of NOMA users. Based on the user pairing, to obtain the optimal resource allocation, a joint optimization algorithm of power allocation, beam channel and base station channel resource is proposed. Finally, simulation results are provided to evaluate the user paring scheme as well as the total system performance, in comparison with the existing works.

Satellite Network Security

2011 ◽  
pp. 3350-3355 ◽  
Author(s):  
Marlyn Kemper Littman
Keyword(s):  
Critical Infrastructure ◽  
Cyber Attacks ◽  
Satellite Networks ◽  
Satellite Network ◽  
Cyber Terrorism ◽  
Department Of Homeland Security ◽  
Public And Private ◽  
Government Accounting ◽  
Terrestrial Networks ◽  
Electromagnetic Signals

Satellite networks play a vital role in enabling essential critical infrastructure services that include public safety; environmental monitoring; maritime disaster recovery and reconnaissance; electronic surveillance; and intelligence operations for law enforcement, the military, and government agencies (Jamalipour & Tung, 2001). As demonstrated by the events following the terrorist attacks in the U.S. on the Pentagon in Washington, D.C. and the World Trade Center in New York City on September 11, 2001, satellite networks also provide redundant communications services when terrestrial networks are disrupted and/or unavailable. Despite their merits, satellite networks are nonetheless vulnerable to cyber attacks that pose threats to national security and the economy. Satellite networks transport voice, video, images, and data through the air as electromagnetic signals, thereby making these transmissions susceptible to interception. Technical advances enable the interconnectivity of satellite systems to public and private wireless and terrestrial networks including the Internet. These advances, however, amplify the risk of cyber attacks that can compromise critical infrastructure functions dependent on satellite networks in sectors that include information technology (IT) and telecommunications; defense; government; banking and finance; utilities; agriculture; emergency services; public health; and transportation (U.S. Department of Homeland Security (DHS), 2003; U.S. Government Accounting Office (GAO), 2004). As a consequence, satellite networks employ an array of security tools and mechanisms for countering costly and widespread cyber incursions and, thereby, ensuring the continuity of critical infrastructure operations. Those cyber attacks that are politically motivated and specifically designed to disrupt essential services are generally attributed to cyber terrorism. This chapter describes the technical fundamentals of satellite networks; examines security vulnerabilities; and explores initiatives for protecting the integrity of satellite network transmissions and operations from cyber incursions and physical attacks. Standards and protocols that safeguard satellite networks from unauthorized use and intentional disruptions and policies, and legislation that facilitate cyberspace asset protection are described. Capabilities of encryption in supporting secure satellite services and the distinctive attributes of the InterPlanetary Internet (IPN), also called the InterPlanetary Network, are explored.

scholarly journals Multiple Unmanned Aerial Vehicles Deployment and User Pairing for Non-Orthogonal Multiple Access Schemes

2020 ◽  
Author(s):  
Jie Wang ◽  
Miao Liu ◽  
Jinlong Sun ◽  
Guan Gui ◽  
Haris Gacanin ◽  
...  
Keyword(s):  
Wireless Communications ◽  
Unmanned Aerial Vehicles ◽  
Message Passing ◽  
Multiple Access ◽  
Base Station ◽  
Spectrum Efficiency ◽  
User Pairing ◽  
Aerial Vehicles ◽  
Multiple Uavs ◽  
Multiple Unmanned Aerial Vehicles

Non-orthogonal multiple access (NOMA) significantly improves the connectivity opportunities and enhances the spectrum efficiency (SE) in the fifth generation and beyond (B5G) wireless communications. Meanwhile, emerging B5G services demand of higher SE in the NOMA based wireless communications. However, traditional ground-to-ground (G2G) communications are hard to satisfy these demands, especially for the cellular uplinks. To solve these challenges, this paper proposes a multiple unmanned aerial vehicles (UAVs) aided uplink NOMA method. In detail, multiple hovering UAVs relay data for a part of ground users (GUs) and share the sub-channels with the left GUs that communicate with the base station (BS) directly. Furthermore, this paper proposes a K-means clustering based UAV deployment and location based user pairing scheme to optimize the transceiver association for the multiple UAVs aided NOMA uplinks. Finally, a sum power minimization based resource allocation problem is formulated with the lowest quality of service (QoS) constraints. We solve it with the message-passing algorithm and evaluate the superior performances of the proposed scheduling and paring schemes on SE and energy efficiency (EE). Extensive experiments are conducted to compare the performances of the proposed schemes with those of the single UAV aided NOMA uplinks, G2G based NOMA uplinks, and the proposed multiple UAVs aided uplinks with a random UAV deployment. Simulation results demonstrate that the proposed multiple UAVs deployment and user pairing based NOMA scheme significantly improves the EE and the SE of the cellular uplinks at the cost of only a little relaying power consumption of the UAVs.

scholarly journals Development of stratospheric communication platforms (SCP) as backbone to terrestrial networks

2020 ◽  
Vol 18 (3) ◽  
pp. 1679
Author(s):  
Dimov Stojce Ilcev
Keyword(s):  
Rural Areas ◽  
Elevation Angle ◽  
Cost Effective ◽  
Cellular Systems ◽  
Obstacle Problems ◽  
Total System ◽  
Cellular Radio ◽  
Coverage Area ◽  
Terrestrial Networks ◽  
Solar Powered

<p align="LEFT"><span style="font-size: xx-small;">In this paper are introduced the new airship techniques and technologies as cost effective solutions of Stratospheric Communication Platforms (SCP) as future backbone of terrestrial networks for rural communications. The launch or putting in position the airship is not critical point such as launch of satellite and controlling support services in the creation of space-based communication technology and the most expensive phase of the total system cost. Therefore, with few cost effective remote controlled and solar powered airships can be covered some region or country including remote and rural areas with low density of population. The airship SCP network offers better solutions than cellular radio systems, with greater speed of transmission than even optical modes, roaming will be enhanced without severe shadowing or obstacle problems and disturbances inside of buildings and service will cost less. The SPS mission system is more autonomous and discrete, can be integrated with current satellite and cellular systems, and will be the best solution for rural, mobile transportation and military applications. The SCP airship can be seen well from all positions inside coverage area, because they are overlapping the total coverage and because of elevation angle. In any circumstances mountains, buildings and even trees cannot cause obstructions like to cellular network. For these reasons, there is currently a revival of interest for SCP constellations and application types of various system concepts are being studied.</span></p><strong><strong></strong></strong><p> </p><strong></strong>

scholarly journals Multiple Unmanned Aerial Vehicles Deployment and User Pairing for Non-Orthogonal Multiple Access Schemes

2020 ◽  
Author(s):  
Jie Wang ◽  
Miao Liu ◽  
Jinlong Sun ◽  
Guan Gui ◽  
Haris Gacanin ◽  
...  
Keyword(s):  
Wireless Communications ◽  
Unmanned Aerial Vehicles ◽  
Message Passing ◽  
Multiple Access ◽  
Base Station ◽  
Spectrum Efficiency ◽  
User Pairing ◽  
Aerial Vehicles ◽  
Multiple Uavs ◽  
Multiple Unmanned Aerial Vehicles

Non-orthogonal multiple access (NOMA) significantly improves the connectivity opportunities and enhances the spectrum efficiency (SE) in the fifth generation and beyond (B5G) wireless communications. Meanwhile, emerging B5G services demand of higher SE in the NOMA based wireless communications. However, traditional ground-to-ground (G2G) communications are hard to satisfy these demands, especially for the cellular uplinks. To solve these challenges, this paper proposes a multiple unmanned aerial vehicles (UAVs) aided uplink NOMA method. In detail, multiple hovering UAVs relay data for a part of ground users (GUs) and share the sub-channels with the left GUs that communicate with the base station (BS) directly. Furthermore, this paper proposes a K-means clustering based UAV deployment and location based user pairing scheme to optimize the transceiver association for the multiple UAVs aided NOMA uplinks. Finally, a sum power minimization based resource allocation problem is formulated with the lowest quality of service (QoS) constraints. We solve it with the message-passing algorithm and evaluate the superior performances of the proposed scheduling and paring schemes on SE and energy efficiency (EE). Extensive experiments are conducted to compare the performances of the proposed schemes with those of the single UAV aided NOMA uplinks, G2G based NOMA uplinks, and the proposed multiple UAVs aided uplinks with a random UAV deployment. Simulation results demonstrate that the proposed multiple UAVs deployment and user pairing based NOMA scheme significantly improves the EE and the SE of the cellular uplinks at the cost of only a little relaying power consumption of the UAVs.

Study of Power Control in CDMA System on the basis of optimization Technique

2017 ◽  
Vol 7 (8) ◽  
pp. 126
Author(s):  
. Geetanjli
Keyword(s):  
Power Control ◽  
Multiple Access ◽  
Optimization Technique ◽  
System Optimization ◽  
Base Station ◽  
Particle Swarm Algorithm ◽  
Cdma System ◽  
Frequency Division ◽  
Cdma Systems ◽  
Time Division

The power control in CDMA systems, grant numerous users to share resources of the system uniformly between each other, leading to expand capacity. With convenient power control, capacity of CDMA system is immense in contrast of frequency division multiple access (FDMA) and time division multiple access (TDMA). If power control is not achieved numerous problems such as the near-far effect will start to monopolize and consequently will reduce the capacity of the CDMA system. However, when the power control in CDMA systems is implemented, it allows numerous users to share resources of the system uniformly between themselves, leading to increased capacity For power control in CDMA system optimization algorithms i.e. genetic algorithm & particle swarm algorithm can be used which regulate a convenient power vector. These power vector or power levels are dogged at the base station and announce to mobile units to alter their transmitting power in accordance to these levels. The performances of the algorithms are inspected through both analysis and computer simulations, and compared with well-known algorithms from the literature.

Resource Allocation Based on User Pairing and Subcarrier Matching for Downlink Non-Orthogonal Multiple Access Networks

2021 ◽  
Vol 8 (3) ◽  
pp. 679-689
Author(s):  
Zhixin Liu ◽  
Changjian Liang ◽  
Yazhou Yuan ◽  
Kit Yan Chan ◽  
Xinping Guan
Keyword(s):  
Resource Allocation ◽  
Multiple Access ◽  
Access Networks ◽  
User Pairing
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