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FCC PART 15, SUBPART C, SEC. 15.247 - DIRECT SEQUENCE SPREAD SPECTRUM TRANSMITTERS
PCMCIA Wireless LAN Card, Model WL-211F
THEORETICAL CALCULATIONS
The processing gain is related to the jamming margin as follows [2]:
S
=
+
G
p
N
output
Where BER
REFERENCE
to noise ratio per symbol, (S/N)
desired signal power), and L
The maximum allowed total system implementation loss is 2 dB.
The HFA3861A direct sequence spread spectrum baseband processor uses CCK modulation which is
a form of M-ary Orthogonal Keying. The BER performance curve is given by [5]:
" The probability of error for generalized M-ary Orthogonal signaling using coherent demodulation is
given by:
=
−
=
−
P
1
P
1
e
c
1
This integral cannot be solved in closed form, and numerical integration must be used. There are
error rate extensions for differential decoding and descrambling that are also to be accounted for.
This is done in a MATHCAD environment and is displayed in graphical format below.
ULTRATECH GROUP OF LABS
3000 Bristol Circle, Oakville, Ontario, Canada L6H 6G4
Tel. #: 905-829-1570, Fax. #: 905-829-8050, Email: vhk.ultratech@sympatico.ca, Website: http://www.ultratech-labs.com
•
Assessed by ITI (UK) Competent Body, NVLAP (USA) Accreditation Body & ACA/AUSTEL (Australia)
•
Accredited by Industry Canada (Canada) under ACC-LAB (Europe/Canada MRA)
•
Recognized/Listed by FCC (USA )
•
All test results contained in this engineering test report are traceable to National Institute of Standards and Technology (NIST)
J
+
L
system
S
is the reference bit error ratio with its corresponding, theoretical output signal
, (J/S) is the jamming margin (jamming signal power relative to
output
are the system implementation losses.
system
∞
1
∫
−
2 1
(
Q z
π
2
S
01
−
N
0
M
2
E
+
b
2
)
η
FCC ID: MXF-WL211F
−
1
2
z
−
exp
dz
2
File #: GTT-013FTX
Page 48
March 17, 2000
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