Patent ID: 8155640

Claim:
A satellite communications method in a mobile terminal, wherein satellite communication between a plurality of mobile terminals and an operation center is supported by a cyclically repeating defined sequence of timeslots, said cyclically repeating defined sequence of timeslots including scheduled reporting timeslot types and unscheduled reporting timeslot types, said scheduled reporting timeslot types capable of being assigned to individual mobile terminals, the method comprising: transitioning from a low power state to an active state at a time proximate to a timeslot of a scheduled reporting timeslot type that has been assigned to said mobile terminal; after transitioning from said low power state to said active state, first transmitting, via a communication satellite, a scheduled report to said operation center on said timeslot of said scheduled reporting timeslot type; after said first transmitting, transitioning from said active state to said low power state; detecting an occurrence of an unscheduled event by said mobile terminal; transitioning from said low power state to said active state upon detection of said occurrence of said unscheduled event; after transitioning from said low power state to said active state, sequentially analyzing a first plurality of timeslots that includes timeslots of said scheduled reporting timeslot type and said unscheduled reporting timeslot type, said analyzing of said plurality of timeslots including an analysis of traffic on timeslots of said scheduled reporting timeslot type; identifying, based on said sequential analysis of said first plurality of timeslots, a first usable timeslot in said first plurality of timeslots, said identified first usable timeslot not being previously assigned to said mobile terminal; transmitting, via said communication satellite, an unscheduled report based on said detected occurrence of said unscheduled event on said identified first usable timeslot; if an acknowledgment of said transmitted unscheduled report is not received, then sequentially analyzing a second plurality of timeslots that begins at a point in said cyclically repeating defined sequence of timeslots greater than a backoff period, said second plurality of timeslots including timeslots of said scheduled reporting timeslot type and said unscheduled reporting timeslot type, said analyzing of said second plurality of timeslots also including an analysis of traffic on timeslots of said scheduled reporting timeslot type, wherein at least two of said second plurality of timeslots are consecutive timeslots that are analyzed in consecutive order; identifying, based on said sequential analysis of said second plurality of timeslots, a second usable timeslot in said second plurality of timeslots, said identified second usable timeslot not being previously assigned to said mobile terminal; and retransmitting said unscheduled report on said identified second usable timeslot.