Packet transmission time in 802.11

Frame exchange duration for a unicast data frame and the acknowledgement frame

To download an editable EXCEL sheet, where you can enter your personal values, click on the following link: File:80211 TransmissionTime.xls.

There you can enter the length of the data packet as well as a few other options to calculate the expected transmission time. Also see the comments in the file. The MAKRO inside the file allows to create wiki output; just deactivate it in case you don't need it.

For 802.11b bitrates (valid in 802.11a*,b and g; short headers used)

	Payload in bytes:	1500
	Short preamble and headers (DSSS):	yes
	Data transmission bitrate (802.11b/g):			1 Mbps				2 Mbps				5,5 Mbps				11 Mbps
			Bitrate (Mbit/s)	Length (bits)	Time (μs)		Bitrate (Mbit/s)	Length (bits)	Time (μs)		Bitrate (Mbit/s)	Length (bits)	Time (μs)		Bitrate (Mbit/s)	Length (bits)	Time (μs)
	DIFS				50				50				50				50
D	PHY header: PLCP preamble		1	144	144		1	72	72		1	72	72		1	72	72
A	PHY header: PLCP header		1	48	48		2	48	24		2	48	24		2	48	24
T	MAC headers (28 bytes) + MAC body		1	12224	12224		2	12224	6112		5,5	12224	2223		11	12224	1111
A	tx time data:				12466				6258				2369				1257
	SIFS				10				10				10				10
A	PHY header: PLCP preamble		1	144	144		1	72	72		1	72	72		1	72	72
C	PHY header: PLCP header		1	48	48		2	48	24		2	48	24		2	48	24
K	MAC headers (28 bytes), no MAC body		1	112	112		2	112	56		5,5	112	21		11	112	11
	tx time ack:				314				162				127				117
	tx time data + ack:				12780				6420				2496				1374
	Basic rate set minimal (6, 12, 24 Mbps):	yes
	Data transmission bitrate (802.11g / a*):			6 Mbps				9 Mbps				12 Mbps				18 Mbps
			Bitrate (Mbit/s)	Length (bits)	Time (μs)		Bitrate (Mbit/s)	Length (bits)	Time (μs)		Bitrate (Mbit/s)	Length (bits)	Time (μs)		Bitrate (Mbit/s)	Length (bits)	Time (μs)
	DIFS				28				28				28				28
D	PHY header: PLCP preamble		-	-	16		-	-	16		-	-	16		-	-	16
A	PHY header: PLCP header		6	24	4		6	24	4		6	24	4		6	24	4
T	MAC headers + MAC body + PHY pad		6	12246	2044		9	12246	1364		12	12246	1024		18	12246	684
A	signal extension time				6				6				6				6
	tx time data:				2098				1418				1078				738
	SIFS				10				10				10				10
A	PHY header: PLCP preamble		-	-	16		-	-	16		-	-	16		-	-	16
C	PHY header: PLCP header		6	24	4		6	24	4		6	24	4		6	24	4
K	MAC headers		6	134	24		6	134	24		12	134	12		12	134	12
	signal extension time				6				6				6				6
	tx time ack:				60				60				48				48
	tx time data + ack:				2158				1478				1126				786
	Data transmission bitrate (802.11g / a*):			24 Mbps				36 Mbps				48 Mbps				54 Mbps
			Bitrate (Mbit/s)	Length (bits)	Time (μs)		Bitrate (Mbit/s)	Length (bits)	Time (μs)		Bitrate (Mbit/s)	Length (bits)	Time (μs)		Bitrate (Mbit/s)	Length (bits)	Time (μs)
	DIFS				28				28				28				28
D	PHY header: PLCP preamble		-	-	16		-	-	16		-	-	16		-	-	16
A	PHY header: PLCP header		6	24	4		6	24	4		6	24	4		6	24	4
T	MAC headers (28 bytes) + MAC body		24	12246	512		36	12246	344		48	12246	256		54	12246	228
A	signal extension time				6				6				6				6
	tx time data:				566				398				310				282
	SIFS				10				10				10				10
A	PHY header: PLCP preamble		-	-	16		-	-	16		-	-	16		-	-	16
C	PHY header: PLCP header		6	24	4		6	24	4		6	24	4		6	24	4
K	MAC headers + PHY pad		24	134	8		24	134	8		24	134	8		24	134	8
	signal extension time				6				6				6				6
	tx time ack:				44				44				44				44
	tx time data + ack:				610				442				354				326

.*) valid for 802.11a with the following change: No signal extension time, SIFS is 16μs instead of 10μs and DIFS should be 34μs instead of 28μs. The overall transmission time stays the same.