Taxonomy and Evaluations of Low-Power Listening Protocols for Machine-to-Machine Networks

Table 2

Notations.

Notation	Description	Value
𝑇PS	Preamble sensing time	15.6 milliseconds
𝑇WS	Wake-up sensing time	183 milliseconds
𝑇FS	Frame sensing time	183 milliseconds
𝑇BS	Beacon sending time	90 milliseconds
𝑇𝑆	Sleep duration	Variable milliseconds
𝑇𝑃	Preamble transmission time for device trigger	(i) Long preamble (B-MAC); (ii) Short preamble (X-MAC); (iii) Variable (Wise-MAC)
𝑇WP	Wake-up packet time for trigger	90 milliseconds
𝑇DP	Data packet time for trigger	150 milliseconds
𝑇BL	Beacon listen time	Random
𝑇𝐵	Back-off period	1 milliseconds
𝑇𝐿	Listen period	Variable
𝑇DT	Data transmission time	200 milliseconds
𝑇ACK	ACK transmission time	90 milliseconds
𝑇DPT	Data pending time	Random
𝑇DC	Duty-cycle time	=𝑇PS+𝑇𝑆 (preamble-based); =𝑇WS+𝑇𝑆 (wake-up packet-based); =𝑇FS+𝑇𝑆 (packet-based); = beacon interval (receiver-initiated)
𝑇tot-active	Total active duration	𝑇𝐴-PPS+𝑇𝐴-aggre (i)
𝑇tot-sleep	Total sleep duration	𝑇interval−𝑇tot-active (ii)
𝑇interval	Request interval	1 hour (=3600 seconds = 3600000 milliseconds)
𝐼𝐴	Current consumption in active state	0.0061944 mA
𝐼𝑆	Current consumption in active state	0.0000083 mA
𝑇𝐴-aggre	Active duration during data aggregation time
𝑇𝐴-PPS	Active duration in a duty cycle
𝑇AW	Acknowledgement waiting period	100 milliseconds
𝑉	Supply voltage	3.5 V