Contiki-NG
tsch-timeslot-timing.c
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1 /*
2  * Copyright (c) 2018, RISE SICS.
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29  * This file is part of the Contiki operating system.
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32 
33 /**
34  * \file
35  * IEEE 802.15.4 TSCH timeslot timings
36  * \author
37  * Simon Duquennoy <simon.duquennoy@ri.se>
38  *
39  */
40 
41 /**
42  * \addtogroup tsch
43  * @{
44 */
45 
46 #include "contiki.h"
47 #include "net/mac/tsch/tsch.h"
48 
49 /**
50  * \brief TSCH timing attributes and description. All timings are in usec.
51  *
52  * CCAOffset -> time between the beginning of timeslot and start of CCA
53  * CCA -> duration of CCA (CCA is NOT ENABLED by default)
54  * TxOffset -> time between beginning of the timeslot and start of frame TX (end of SFD)
55  * RxOffset -> beginning of the timeslot to when the receiver shall be listening
56  * RxAckDelay -> end of frame to when the transmitter shall listen for ACK
57  * TxAckDelay -> end of frame to the start of ACK tx
58  * RxWait -> time to wait for start of frame (Guard time)
59  * AckWait -> min time to wait for start of an ACK frame
60  * RxTx -> receive-to-transmit switch time (NOT USED)
61  * MaxAck -> TX time to send a max length ACK
62  * MaxTx -> TX time to send the max length frame
63  *
64  * The TSCH timeslot structure is described in the IEEE 802.15.4-2015 standard,
65  * in particular in the Figure 6-30.
66  *
67  * The default timeslot timing in the standard is a guard time of
68  * 2200 us, a Tx offset of 2120 us and a Rx offset of 1120 us.
69  * As a result, the listening device has a guard time not centered
70  * on the expected Tx time. This is to be fixed in the next iteration
71  * of the standard. This can be enabled with:
72  * TxOffset: 2120
73  * RxOffset: 1120
74  * RxWait: 2200
75  *
76  * Instead, we align the Rx guard time on expected Tx time. The Rx
77  * guard time is user-configurable with TSCH_CONF_RX_WAIT.
78  * (TxOffset - (RxWait / 2)) instead
79  */
80 
82  1800, /* CCAOffset */
83  128, /* CCA */
84  2120, /* TxOffset */
85  (2120 - (TSCH_CONF_RX_WAIT / 2)), /* RxOffset */
86  800, /* RxAckDelay */
87  1000, /* TxAckDelay */
88  TSCH_CONF_RX_WAIT, /* RxWait */
89  400, /* AckWait */
90  192, /* RxTx */
91  2400, /* MaxAck */
92  4256, /* MaxTx */
93  10000, /* TimeslotLength */
94 };
95 
96 /** @} */
Main API declarations for TSCH.
uint16_t tsch_timeslot_timing_usec[tsch_ts_elements_count]
TSCH timeslot timing elements in micro-seconds.
Definition: tsch-types.h:149
const tsch_timeslot_timing_usec tsch_timeslot_timing_us_10000
TSCH timing attributes and description.