On-the-fly inroute adaptive modulation

A system that performs adaptive modulation of terminal to satellite communications, the system comprising:

• a terminal that is in communication with a gateway system via a satellite and a satellite antenna, wherein the terminal comprises one or more non-transitory processor-readable mediums and the terminal is configured to:
• receive power level feedback from the satellite, wherein the power level feedback is indicative of a received power level of a data transmission previously sent from the terminal to the satellite;
• access a feedback data structure stored using the one or more non-transitory processor-readable mediums to perform a lookup based on the received power level, wherein:
• the feedback data structure maps a plurality of error correcting code rates with a plurality of minimum power level thresholds;
• the feedback data structure comprises a plurality of entries;
• each entry of the plurality of entries maps one of the plurality of error coding rates with one of the plurality of minimum power level thresholds;
• the plurality of entries of the feedback data structure are ranked according to the plurality of minimum power level thresholds;
• and
• each of the plurality of minimum power level thresholds are mapped to a same symbol rate;
• based on performing the lookup based on the received power level in the feedback data structure, determine the received power level is not greater than any of the plurality of minimum power level thresholds;
• determine to decrease a symbol rate in response to determining that the received power level is not greater than any of the plurality of minimum power level thresholds;
• and
• transmit data packets to the satellite using a decreased symbol rate in response to determining that the received power level is not greater than any of the plurality of minimum power level thresholds mapped to the same symbol rate.