Communication circuitry that employs persistent scheduling conventionally uses one initiation command to establish the modulation and coding scheme (“MCS”) that will be used for transmission of subsequent payload bursts, at least until it is time to send another initiation command. Inefficiency can result if transmission channel conditions change between initiation commands. To avoid such inefficiency, the disclosed circuitry maintains a count of unsuccessful transmission attempts. When the count deviates from a predetermined reference standard, the circuitry automatically and autonomously makes an appropriate change in the MCS selection without waiting for the next initiation command. Both transmitter and receiver circuits independently operate in the same way at the same time so that both ends of a communication link remain coordinated with one another.