OfficeServ 500 Wireless LAN Service Manual/Ed.00
Annex A. WLAN(802.11b/DSSS) Specifications
© SAMSUNG Electronics Co., Ltd.
Annex A-3
3
Definitions and Features by Layer
3.1 Physical
Layer
DSSS Physical Layer
DSSS physical layer diffuses data to 11 bit Barker words before sending the data.
11 bit Barker words have 10.4 dB of processing gain that meets FCC Part 15.247.
All clients use the same 11 bit Barker words.
DSSS physical layer has a total of 14 channels and null-to-null bandwidth is 22 MHz.
Frequency scope is from 2.400 MHz through 2.483 MHz. It has 3 non-overlapping
channels.
Modulation ways for each data rate and other information are as follows.
Table A.3 Information on the Data Rate of DSSS Physical Layer
Data Rate
Code Length
Modulation
Symbol Rate
Bits/Symbol
1 Mbps
11(Barker Sequence) BPSK
1 MSps
(Mega Symbol per Sec)
1
2 Mbps
11(Barker Sequence) QPSK
1 MSps
2
5.5 Mbps
8(CCK)
QPSK
1.375 MSps
4
11 Mbps
8(CCK)
QPSK
1.375 MSps
8
FHSS Physical Layer
FHSS physical layer supports 2 level GFSK 1 Mbps of basic rate as well as 4 level
GFSK 2Mbps optionally.
It has 79 channels and the bandwidth of each channel is 1 MHz. It hops 2.5 per
second. This is a provision for spreading in FCC Part 15.247. FHSS physical layer
has 22 hop patterns as well.
Infrared Physical Layer
Infrared physical layer uses pulse position modulation(PPM) having 4 or 6 levels.
Operating data rates are 1 Mbps and 2 Mbps.
