
USER’S MANUAL OF WLAN BROADBAND ROUTER
Version: 1.0
69
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The 802.11n draft specifies two guard intervals: 400ns (short) and 800ns (long).
Support of the 400ns GI is optional for transmit and receive. The purpose of a guard
interval is to introduce immunity to propagation delays, echoes, and reflections to which
digital data is normally very sensitive.