10-03-2011, 04:00 PM
802.11n Seminar Presentation1.ppt (Size: 1.5 MB / Downloads: 89)
802.11 Protocol(WLan Standard)
Introduction:
Access anytime, anywhere internet.
IEEE 802.11 is a set of standards for wireless Local Area Networks
(WLANs) computer communication, developed by the IEE LAN/MAN Standards Committee.
1997 working group approved IEEE 802.11 as the world’s first wireless LAN standard.
IEEE 802.11 is a subset of IEEE 802 LAN standard.
IEEE 802.11 Protocol:
Covers physical and data link layer acc. to OSI
Physical layer:
Data Link layer
Spread Spectrum
Logic Link Control (LLC)
Media Access Control (MAC)
IEEE 802.11 standards :
IEEE 802.11 standards
IEEE 802.11 b
IEEE 802.11 a
IEEE 802.11 g
IEEE 802.11 n
IEEE 802.11 b
Frequency = 2.4 GHz (ISM band)
Maximum Speed =11 Mbps
Range = about 38meters(Varies)
Encoding Scheme = DSSS
Modulation Technique= BPSK(1 Mbps),
DQPSK(2 Mbps), CCK(5.5 Mbps,11Mbps)
IEEE 802.11 a
Orthogonal Frequency Division Multiplexing(OFDM)
OFDM a digital multi-carrier modulation method. A large
number of closely-spaced orthogonal sub-carriers are used to
carry data.
Although the principles and some of the benefits have
been known since the 1960s, OFDM is popular for
wideband communications today by way of low-cost digital
signal processing components that can efficiently calculate
the FFT.