US Patent No. 9,294,323

EXTENDED GUARD INTERVAL FOR OUTDOOR WLAN


Patent No. 9,294,323
Issue Date March 22, 2015
Title Extended Guard Interval For Outdoor Wlan
Inventorship Hongyuan Zhang, Fremont, CA (US)
Assignee MARVELL WORLD TRADE LTD., St. Michael (BB)

Claim of US Patent No. 9,294,323

1. A method for generating a data unit for transmission via a communication channel, the method comprising:
generating a data portion of the data unit, including generating orthogonal frequency division multiplexing (OFDM) symbols
of the data portion using a guard interval selected from a set of guard intervals that includes (i) a normal guard interval,
(ii) a short guard interval, and (iii) a long guard interval;

generating a preamble of the data unit, including generating the preamble to indicate whether at least OFDM symbols of the
data portion are generated using the normal guard interval, the short guard interval, or the long guard interval, wherein,
when the at least OFDM symbols of the data portion are generated using the long guard interval, generating the preamble includes
(i) generating two or more repetitions of a legacy signal field, and (ii) including the two or more repetitions of the legacy
signal field in the preamble, wherein presence of the two or more repetitions of the legacy signal field in the preamble serves
as an indication that the at least OFDM symbols of the data portion are generated using the long guard interval; and

generating the data unit to include the preamble and the data portion.