ot::CslTxScheduler::ChildInfo class

The time in units of 10 symbols from the first symbol of the frame containing the CSL IE was transmitted until the next channel sample, see IEEE 802.15.4-2015, section 6.12.2. The Thread standard further defines the CSL phase (see Thread 1.4, section 3.2.6.3.4, also conforming to IEEE 802.15.4-2020, section 6.12.2.1): * The "first symbol" from the definition SHALL be interpreted as the first symbol of the MAC Header. * "until the next channel sample": * The CSL Receiver SHALL be ready to receive when the preamble time T_pa as specified below is reached. * The CSL Receiver SHOULD be ready to receive earlier than T_pa and SHOULD stay ready to receive until after the time specified in CSL Phase, according to the implementation and accuracy expectations. * The CSL Transmitter SHALL start transmitting the first symbol of the preamble of the frame to transmit at the preamble time T_pa = (CSL-Phase-Time – 192 us) (that is, CCA must be performed before time T_pa). Here, CSL-Phase-Time is the time duration specified by the CslPhase field value (in units of 10 symbol periods). * This implies that the CSL Transmitter SHALL start transmitting the first symbol of the MAC Header at the time T_mh = CSL-Phase-Time. Derivation of the next TX timestamp based on this definition and the RX timestamp of the packet containing the CSL IE: Note that RX and TX timestamps are defined to point to the end of the synchronization header (SHR). lastTmh = lastRxTimestamp + phrDuration nextTmh = lastTmh + symbolPeriod * 10 * (n * cslPeriod + cslPhase) = lastTmh + 160us * (n * cslPeriod + cslPhase) nextTxTimestamp = nextTmh - phrDuration = lastRxTimestamp + 160us * (n * cslPeriod + cslPhase).