USER’S MANUAL OF WNAP 3G MOBILE ROUTER Version: 1.4
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4.34 What is Guard Intervals (GI)?
A GI is a period of time between symbol transmission that allows reflections (from
multipath) from the previous data transmission to settle before transmitting a new
symbol.
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.
