Starlink

SpaceX's Starlink network currently has more than 6,000 satellites in orbit.

Starlink is SpaceX's low-Earth orbit satellite internet service, with satellites deployed in orbits approximately 550 kilometers above Earth's surface.

The Starlink constellation's orbital scheduling, signal interference avoidance, and ground station handovers require real-time computing capability, creating continuous and rigid demand for GPUs.

The StarRTT framework integrates per-second serving-satellite identification and RTT prediction into a single end-to-end framework, no longer waiting for the scheduling period to end before updating satellite information, but instead continuously identifying the serving satellite at second-level granularity and feeding it into the prediction model in real time.

In high-frequency handover scenarios such as Starlink, identification blind spots may cover most of the RTT variation period, leaving the prediction model able to rely only on historical RTT extrapolation and unable to use real-time geometric relationships to correct forecasts.

There is a lack of specific data on the start and end times of the throttling and the scope of impact (whether it is area-wide or limited to specific terminals).

Reports say Elon Musk ordered SpaceX to throttle Starlink access in Ukraine.

SpaceX already provides satellite broadband service through Starlink and has partnered with T-Mobile to launch a direct-to-satellite phone service supporting text messages and voice calls.

Direct-to-satellite service initially supports only text messages and low-speed voice, making it difficult to carry large-scale data traffic in dense urban areas.

Pure satellite solutions have limited capacity in densely populated areas and struggle to support large-scale mobile data demand, so SpaceX needs terrestrial base stations to supplement capacity.

SpaceX's long-term vision is to build a communications network with seamless global coverage, combining wide-area satellite coverage with terrestrial base station capacity.

SpaceX has reached partnerships with multiple operators, making satellite direct-to-phone a core scenario of next-generation connectivity solutions.

In their joint letter of intent, the four operators explicitly mention "supporting European direct-to-device satellite competition," treating Starlink as a competitive force to be directly hedged against rather than a mere partner, and choosing an option that "does not include Starlink."

Starlink's push in the direct-to-device field is mainly advanced through its "Direct to Cell" capability, relying on large-aperture satellites with phased-array antennas to cooperate with ground operators so that existing LTE phones can access the satellite network in areas without ground signal coverage.

Starlink's Direct to Cell business has proven the technical path of direct satellite-to-ordinary-phone connectivity feasible, but current capabilities mainly support SMS and basic data services.

Starlink is SpaceX's low-Earth-orbit satellite internet service.

Starlink's ground infrastructure includes gateway stations, user terminals and backhaul links.

Low-Earth-orbit satellite internet (LEO) refers to satellite constellation systems operating in orbits about 300 to 2,000 kilometers above the ground.

Starlink's architecture has a certain degree of redundancy: a single satellite failure can be covered by other satellites, and ground gateways also have multi-site backups.

The available bandwidth of a single low-orbit satellite is typically on the order of a few Gbps to tens of Gbps, and the total capacity of a ten-thousand-satellite constellation at theoretical peak is only equivalent to the transmission capacity of a few high-capacity submarine cables.