Massive MIMO Transmission for LEO Satellite Communications

135

The 5G wireless communication network is currently faced with the challenge of limited data speed exacerbated by the proliferation of billions of data-intensive applications. To address this problem, researchers are developing cutting-edge technologies for the envisioned 6G wireless communication standards to satisfy the escalating wireless services demands. Though some of the candidate technologies in the 5G standards will apply to 6G wireless networks, key disruptive technologies that will guarantee the desired quality of physical experience to achieve ubiquitous wireless connectivity are expected in 6G. This article first provides a foundational background on the evolution of different wireless communication standards to have a proper insight into the vision and requirements of 6G. Second, we provide a panoramic view of the enabling technologies proposed to facilitate 6G and introduce emerging 6G applications such as multi-sensory–extended reality, digital replica, and more. Next, the technology-driven challenges, social, psychological, health and commercialization issues posed to actualizing 6G, and the probable solutions to tackle these challenges are discussed extensively. Additionally, we present new use cases of the 6G technology in agriculture, education, media and entertainment, logistics and transportation, and tourism. Furthermore, we discuss the multi-faceted communication capabilities of 6G that will contribute significantly to global sustainability and how 6G will bring about a dramatic change in the business arena. Finally, we highlight the research trends, open research issues, and key take-away lessons for future research exploration in 6G wireless communication.

Section: Enabling Technologies and Challenges For 6gmentioning

confidence: 99%

6G Enabled Smart Infrastructure for Sustainable Society: Opportunities, Challenges, and Research Roadmap

Imoize

Adedeji

Tandiya

et al. 2021

135

“…Motivated by the latest developments in 5G technologies, some works have proposed approaches to massive MIMO for satellite communications [27], where the key challenges to adopt massive MIMO in satellites are studied. The work in [28] further works in this direction and exploits massive MIMO when a large-scale active phased array antenna system is equipped at the LEO satellite side. We propose to further work in this direction and design adaptive beamformers for direct radiating arrays.…”

Section: Massive Mimo In Leo Satellites For Massive Iotmentioning

confidence: 99%

Smart Beamforming for Direct LEO Satellite Access of Future IoT

Caus

Pérez-Neira

Mendez

2021

Non-terrestrial networks (NTN) are expected to play a key role in extending and complementing terrestrial 5G networks in order to provide services to air, sea, and un-served or under-served areas. This paper focuses the attention on the uplink, where terminals are able to establish a direct link with the NTN at Ka-band. To reduce the collision probability when a large population of terminals is transmitting simultaneously, we propose a grant-free access scheme called resource sharing beamforming access (RSBA). We study RBSA for low Earth orbit (LEO) satellite communications with massive multiple-input multiple-output (MIMO). The idea is to benefit from the spatial diversity to decode multiple overlapped signals. We have devised a blind and open-loop beamforming technique, where neither the receiver must carry out brute-force search in azimuth and elevation, nor are the terminals required to report channel state information. Upon deriving the theoretical throughput, we show that RBSA is appropriate for grant-free access to LEO satellite, it reduces the probability of collision, and thus it increases the number of terminals that can access the media. Practical implementation aspects have been tackled, such as the estimation of the required statistics, and the determination of the number of users.

“…There are essentially three types of orbits classified by the satellite altitude: geostationary earth orbit (GEO), medium earth orbit (MEO), and low earth orbit (LEO) [ 32 , 33 , 34 ]. Among them, GEO satellites are stationary relative to the earth’s surface so that the doppler shift is negligible and has a lower transmission outage probability than non-GEO satellites [ 32 , 35 , 36 ].…”

Section: Satellite-aided Consensus Protocolmentioning

confidence: 99%

“…However, the existing space blockchain solutions have not fully considered the characteristics of satellite communications, such as delay, link budget, bandwidth, on-board resources [ 16 , 32 , 33 ]. These solutions rely on the conventional, costly mining such as PoW, and use satellites merely as relays to forward blocks for unserved and under-served areas (e.g., BlockStream and ChainSat), or accelerate information diffusion in the mining network (e.g., [ 19 , 20 ]).…”

Section: Introductionmentioning

confidence: 99%

Satellite-Aided Consensus Protocol for Scalable Blockchains

Ling

Gao

et al. 2020

Self Cite

In this work, we propose a satellite-aided permissionless consensus protocol for scalable space–terrestrial blockchains. We design its working principle and workflow by taking full advantage of satellites for extensive coverage and ubiquitous connectivity. Based on the proposed protocol, we demonstrate how such a space–terrestrial blockchain grows and evolves through several typical cases in the presence of adversarial nodes, user misbehavior, and transmission outage. Taking proof of work (PoW) as a benchmark, we assess the system security by considering both adversarial miners and possible colluding satellites. Then, we analyze the maximum blockchain throughput under network capacity limits and evaluate the impact of information propagation delay via a Markov model. Simulation results support that the proposed satellite-aided consensus protocol achieves higher throughput and exhibits greater scalability than PoW.