Massive Multiple-Input Multiple-Output (massive MIMO) is a variant of multi-user MIMO in which the number of antennas at each Base Station (BS) is very large and typically much larger than the number of users simultaneously served. Massive MIMO can be implemented with Time Division Duplexing (TDD) or Frequency Division Duplexing (FDD) operation. FDD massive MIMO systems are particularly desirab...

Dynamic time-division duplexing (TDD) allows for flexible resource allocation the varying downlink (DL) and uplink (UL) traffic demands in 5G cellular network. It becomes more useful when number of active users is highly limited, especially small cells a ultra-dense However, imbalance between DL UL adjacent incurs crosslink interference (CLI), which may seriously reduce system throughput. In or...

the goal of this research is the derivation of method for evaluation of efficiency improvement potential for district heating systems with focus on variable speed centrifugal pump. the effectiveness of the usage of the proportional pressure control is compared with the constant pressure control. this is why, energy calculation analyses have been realized for variable speed centrifugal pumps, an...

it seems that the general applicability of the quantum theory of atoms in molecules (qtaim) oncharacterizing the bonded interactions is still questionable even afier 30 years since its formulation. fordemonstrating the generality of bonding schemes in qta im, ea( isomers were chosen as the modelsystems and the results from molecular charge density analysis and vibrational normal modes werecompa...

This paper deals with channel estimation in reconfigurable intelligent surface (RIS) aided multiple-input multiple-output (MIMO) time-division duplexing systems. In a typical RIS assisted communication, an is deployed the close proximity of communication devices, thus resulting ill-conditioned low-rank matrices. To effectively estimate these channels, we propose two-stage method. Specifically, ...