Transcript 2.4-GHZ RF TRANSCEIVER FOR IEEE 802.11B WIRELESS LAN UF# 1593 6620

2.4-GHZ RF TRANSCEIVER
FOR IEEE 802.11B WIRELESS
LAN
UF# 1593 6620
Objective:
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Design of a system level 2.4 GHz RFtransceiver for wireless LAN
Software used:
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Ansoft
Syscal
MatLab
IEEE 802.11b Specifications
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Receiver:
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Frequency range: 2.4 – 2.4835 GHz
Bit Rate: 1/2/5.5/11 Mb/s
BW: 22 MHz
Sensitivity: -80/-76 dBm
FER: 8%
Adjacent channel Rej: 41 dB
Max Power level: -15 dBm
Receiver NF: 8.3 dB
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Transmitter:
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Max transmit power: 30 dBm
Transmit Spectrum mask
fc = 0 dBr
fc -22MHz <f < fc -11MHz -30 dBr
fc -11MHz < f < fc +22MHz -30 dBr
f < fc-22MHz -50 dBr
f > fc+22MHz -50 dBr
Center frequency tolerance:+/- 25 MHz
Transmitter Architecture
 Transmitter Specifications:
a) o/p power spectrum : -15 dBm
b) 11 Mb/s CCK modulation
c) 1 Mb/s Data rate
d) Barker Code: 10110111000
Specification of parts used in TX
IF Mixer:
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AD8343 < Analog Devices >
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Conversion Gain: 7.1
dB
Input IP3: 16.5 dBm
LO power: 20 dbm
Noise Figure: 14.1 dB
Input P1 dB: 2.8 dB
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IF-SAW filter
< BethelTronix>:
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Center Frequency: 300
MHz.
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Stopband Rejection: 53
dB.
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Insertion Loss: 4.5 dB
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RF Mixer:
HMC400MS8 < Hittite
Corporation >
Conversion Loss: 8.8 dB
Input IP3: 35 dBm
LO power: 18 dBm
Noise Figure: 8.8
Input P1 dB: 22 dBm
RF- Band Pass Filter:
Insertion Loss: 1.1 dB
Center Frequency: 2400 MHz.
Attenuation at cutoff
frequencies: 50 dB
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Power amplifiers:
HMC287MS8 < Hittite
Corporation >
Gain: 21 dB
Noise Figure: 2.2 dB
OP3: 7 dBm
OP1: 3 dBm
GBH120_214 < Alpha >
Gain: 18 dB
IP3: 33 dBm
Noise Figure: 4.5 dB
Transmit Spectrum
Constellation at TX Output
Receiver Architecture
Specifications of the parts used in RX
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RF- Band Pass Filter
< Butterworth >:
Insertion Loss: 1.1 dB
Center Frequency: 2400
MHz.
Attenuation at cutoff
frequencies: 50 dB
 LNA
HMC287MS8 < Hittite
Corporation >
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Gain: 21 dB
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Noise Figure: 2.2 dB
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OP3: 7 dBm
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OP1: 3 dBm
Mixer
HMC400MS8 < Hittite
Corporation >
Conversion Loss: 8.8 dB
Input IP3: 35 dBm
LO power: 18 dBm
Noise Figure: 8.8
Input P1 dB: 22 dBm
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IF-SAW filter
< BethelTronix>:
Center Frequency: 300
MHz.
Stopband Rejection: 53
dB.
Insertion Loss: 4.5 dB
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AD8343 < Analog Devices >
Conversion Gain: 7.1 dB
Input IP3: 16.5 dBm
LO power: 20 dbm
Noise Figure: 14.1 dB
Input P1 dB: 2.8 dB
Low Pass Filter < LPM50001,
Micro-tronics >
Insertion Loss: 3 dB
Pass band: 0-18 MHz
Rejection: 50 dB
Stop band: 19.1 to 100 MHz.
VSWR: 1.5:1
Receiver Requirements
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SNR
FER = 810-2
1 Frame = 1024  8 bits
Let F be the probability that a frame is received correctly,
F100 = 0.92
Let (1-P) be the probability a bit is in error
P1024*8 = F
P = 0.92(1/ (1024*8*100))
1-P = 1.0110-7
Therefore, BER = 1.0110-7
E/N = (erfinv (1-2*BER)) ^2
E/N = 13.5 dB
S/N = 13.5-3
S/N = 10.5 dB
Adhering to a stricter margin, the S/N can be decided to be 12.3 dB
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Noise Figure
Sensitivity = NF + SNR + Noise Floor.
-80 = -174 + 10×log (22×106) +12+NF
NF = 8.3 dB
The noise figure of the receiver should be <= 8.3 dB.
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IIP3
Adjacent channel carrier power= sensitivity+41 dB
Carrier power of channel of interest = sensitivity+6 dB
Therefore the MDS (minimum discernable signal) is –80+6-SNR=
-80+6-10.5 = -84.5
Carrier power of adjacent channel = -80+41= -39
IIP3 = -39 + (-39-(-84.5))/2 = -16.25
Therefore IIP3 for a receiver should be higher than –16.25.
Link Budget Analysis (Syscal)
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IIP3
From the previous figure, we find the IIP3 of the
receiver to be -16.13 dBm, which is >-16.35 dBm
Noise Figure
The NF of the receiver system is 8.46 dB
Variation of parameters with probe location
Summary-Transceiver Specifications
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Heterodyne Architecture:
IF=300 MHz , RF=2.4 GHz
Transmitter Specifications
Data Rate = 1 Mb/s interleaved on 11 Mb/s Barker Code
O/P Power = -15 dBm
Receiver Specifications
Noise Figure = 8.46 dB
Gain = 20.20
OIP3 = 4.07 dBm
Min SNR = 12.3