It is a type of Pulse modulation as in PPM the position of pulse of carrier pulse train is varied in accordance with the modulating signal.

Pulse position modulation offers high noise immunity, efficient use of bandwidth, and easy implementation with digital circuits. This modulation technique is particularly useful in applications requiring high data transmission rates and reliable communication in noisy environments.

pulse position modulation, used in many RC model aircraft controls.

Pulse width mod, pulse amplitude mod, pulse position mod, pulse code mod.

The width of the pulse in PPM is not important, but is usually very narrow and constant in any given PPM system.