Joint Beam Hopping and Carrier Aggregation in High Throughput Multibeam Satellite Systems

Abstract

Beam hopping (BH) and carrier aggregation (CA) are two promising technologies for the next generation satellite communication systems to achieve several orders of magnitude increase in system capacity and to significantly improve the spectral efficiency. While BH allows a great flexibility in adapting the offered capacity to the heterogeneous demand, CA further enhances the user quality-ofservice (QoS) by allowing it to pool resources from multiple adjacent beams. In this paper, we consider a multi-beam high throughput satellite (HTS) system that employs BH in conjunction with CA to capitalize on the mutual interplay between both techniques. Particularly, an innovative joint BH-CA scheme is proposed and analyzed in this work to utilize their individual competencies. This includes designing an efficient joint time-space beam illumination pattern for BH and multi-user aggregation strategy for CA. Through this, user-carrier assignment, transponder filling-rates, beams hopping pattern, and illumination duration are all simultaneously optimized by formulating a joint optimization problem as a multi-objective mixed integer linear programming problem (MINLP). Simulation results are provided to corroborate our analysis, demonstrate the design tradeoffs, and point out the potentials of the proposed joint BH-CA concept. Advantages of our BH-CA scheme versus the conventional BH method without employing CA are investigated and presented under the same system circumstances.

Stem cells derived exosomes as biological nano carriers for VCR sulfate for treating breast cancer stem cells

“…They are extracellular vesicles that are used as signals in cell-to-cell communication in the body 27 . Lately, they have shown impressive results in delivering chemotherapeutics to specific cell types 28 , 29 . In this current study, the loading of Vincristine sulfate with MSC-Exos was investigated as a potential approach to enhance the targeting and specificity of the drug.…”

Stem Cells Derived Exosomes Vincristine Sulfate Loaded as Potential Biological Nano Carriers for Treatment of Breast Cancer Stem Cells

“…They are extra cellular vesicles which are used as signals in cell to cell communication in the body 20 . Lately they showed impressive results in delivering chemotherapeutics to speci c cell types 21,22 . In this current study, the loading of Vincristine sulfate with MSC-Exos was investigated as a potential approach to enhance the targeting and speci city of the drug.…”

Combining Time-Flexible GEO Satellite Payload With Precoding: The Cluster Hopping Approach

“…For example, assume N = 67 and K = 17 beams can be simultaneously activated in a time slot. The total number of reliable snapshots is 15 which is an extremely substantial number just for only one time slot. This number will increase exponentially if the whole window with T time slots is considered.…”

“…While BH enables flexibility to adapt the offered capacity to the heterogeneous demand, precoding strives to improve the spectral efficiency [13], [14]. Conventional BH exploits the time-domain flexibility to provide all available spectrum to a selected set of beams as long as they are not adjacent to each other [15]. With conventional BH, all the available satellite resources are employed to provide service to a certain subset of beams, which is active till the requested demand in each beam is satisfied.…”