An Optimized WSN Design for Latency-Critical Smart Grid Applications

Table 2

Optimization parameters.

Parameter	Definition	Expression/value
	The number of nodes available in a single cluster	Assumed in the scenario under study
	The size of the frames sent	Assumed in the scenario under study
	The size of the ACK frame	Assumed in the scenario under study
	The time unit () defined in the 802.15.4 standard [1]	20 symbols
	Size of the backoff window	is between 0 and
	The probability of finding the wireless medium busy during CCA1	(3)
	The probability of finding the wireless medium busy during CCA2	(4)
	Approximated	(5)
	The approximate probability of being in the first backoff stage with both backoff and retransmission counters in their initial states	(6)
	Approximated	(7)
	The probability that a node starts CCA1 in any time slot
		0–5 (: 4)
	The probability of finding either CCA1 or CCA2 busy	(8)
	The probability of having a collision times
	The probability of collision	(11)
	macMaxFrameRetries	0–7 (Default 3)