Design of cellular, satellite, and integrated systems for 5G and beyond

5G AgiLe and fLexible integration of SaTellite And cellulaR (5G-ALLSTAR) is a Korea-Europe (KR-EU) collaborative project for developing multi-connectivity (MC) technologies that integrate cellular and satellite networks to provide seamless, reliable, and ubiquitous broadband communication services and improve service continuity for 5G and beyond. The main scope of this project entails the prototype development of a millimeter-wave 5G New Radio (NR)-based cellular system, an investigation of the feasibility of an NR-based satellite system and its integration with cellular systems, and a study of spectrum sharing and interference management techniques for MC. This article reviews recent research activities and presents preliminary results and a plan for the proof of concept (PoC) of three representative use cases (UCs) and one joint KR-EU UC. The feasibility of each UC and superiority of the developed technologies will be validated with key performance indicators using corresponding PoC platforms. The final achievements of the project are expected to eventually contribute to the technical evolution of 5G, which will pave the road for next-generation communications

BEYOND THE GUTZWILLER APPROXIMATION IN THE SLAVE-BOSON APPROACH: INCLUSION OF FLUCTUATION WITH THE CORRECT CONTINUUM LIMIT OF THE FUNCTIONAL INTEGRAL

We study the single-band Hubbard model via the functional-integral four-slave-boson formulation introduced by Kotliar and Ruckenstein .

Anomalous pressure dependence of the La2CuO4 superexchange interaction: An evidence of band antiferromagnetism?

We suggest that the weak pressure dependence of the superexchange interaction J recently reported for ..

Exact criterion for choosing the hopping operator in the four-slave-boson approach

We consider the N-component generalization of the four-salve-boson approach to the Hubbard model, where 1/ N acts as a small parameter ..

Doping-induced incommensurate antiferromagnetism in a Mott-Hubbard insulator

Properties of incommensurate spiral spin phases are calculated at the mean-field level for a single-band Hubbard Hamiltonian with variable hole density ..

Consistent 1/N expansion for the four-slave-boson approach with an appropriate operator-ordering prescription

We study the single-band Hubbard model with arbitrary on-site repulsion U within the four-slave-boson approach. We evaluate 1/N corrections ..