Abdul-Aziz.M Al-Yami Khurram Masood Case Study: Phase III Transmitter Receiver Simulation.
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Transcript of Abdul-Aziz.M Al-Yami Khurram Masood Case Study: Phase III Transmitter Receiver Simulation.
Abdul-Aziz .M Al-Yami Abdul-Aziz .M Al-Yami Khurram MasoodKhurram Masood
Case Study: Phase III Transmitter Receiver SimulationTransmitter Receiver Simulation
Physical Layer (PHY)Physical Layer (PHY)
The standard specifies the following four PHYs:1. An 868/915 MHz direct sequence spread spectrum (DSSS) PHY
employing binary phase-shift keying (BPSK) modulation2. An 868/915 MHz DSSS PHY employing offset quadrature phase-
shift keying (O-QPSK) modulation3. An 868/915 MHz parallel sequence spread spectrum (PSSS) PHY
employing BPSK and amplitude shift keying (ASK) modulation4. A 2450 MHz DSSS PHY employing O-QPSK modulation
04/21/23 2
Frequency bands and data ratesFrequency bands and data rates
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4
Frequency bands and data ratesFrequency bands and data rates
2.4 GHz PHY – channels 11-265 MHz
2.4 GHz 2.4835 GHz
902 MHz 928 MHz
Channels 1-10
868.3 MHz
Channel 0
868 / 915 MHz PHY
2 MHz
5
PHY – 2.4 GHz ModePHY – 2.4 GHz Mode
• Each symbol (i.e. 4 bits) is represented by one of 16 32-chip sequences
• First 8 sequences are cyclic shifts of one 32-chip sequence, last 8 are cyclic shifts of another sequence (see next slide)
6
……
PHY – 2.4 GHz ModePHY – 2.4 GHz Mode
7
PHY – 2.4 GHz ModePHY – 2.4 GHz Mode
• Chip modulation is offset-QPSK, in which the Q-branch signal is delayed by one chip period (Tc) with respect to the I-branch signal
• Pulse shape is half-sine with period 2Tc
8
PHY – 2.4 GHz ModePHY – 2.4 GHz Mode
Offset-QPSK with half-sine pulse shaping
9
PHY – 868/915 MHz ModePHY – 868/915 MHz Mode
• Raw bits are differentially encoded– XOR between current bit and the previous encoded bit
• Each coded bit mapped to a 15-chip PN sequence– Zero to 1 1 1 1 0 1 0 1 1 0 0 1 0 0 0– One to 0 0 0 0 1 0 1 0 0 1 1 0 1 1 1 (zero’s complement)
• BPSK modulation with raised cosine pulse shaping with roll-off = 1.0 (100 % excess bandwidth)
2450 MHz DSSS PHY with O-QPSK2450 MHz DSSS PHY with O-QPSK
A 2450 MHz DSSS PHY employing O-QPSK modulation provides250 kbps data rate
04/21/23 10
BER vs SNRBER vs SNR
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0 1 2 3 4 5 610
-5
10-4
10-3
10-2
10-1
EbN0
BE
R2450 MHz band O-QPSK PHY at 250kb/s
869/915 MHz DSSS PHY with BPSK869/915 MHz DSSS PHY with BPSK
868/915 MHz BPSK PHY, provides 20 kb/s in the 868 MHz band and 40 kb/s in the 915 MHz band
04/21/23 12
BER vs SNRBER vs SNR
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0 1 2 3 4 5 6 7 8 9 1010
-5
10-4
10-3
10-2
10-1
EbN0
BE
R868 MHz band BPSK PHY at 20kb/s
Semi-analytic Simulation (No ISI)Semi-analytic Simulation (No ISI)
04/21/23 14
0 2 4 6 8 10 12 14
0.04
0.045
0.05
0.055
0.06
0.065
x-y
cros
scor
rela
tion
Computed Delay
Delay Estimation
Semi-analytic Simulation (No ISI)Semi-analytic Simulation (No ISI)
04/21/23 15
0 5 10 15 20 25 30 35-20
-10
0
10
20D/Q EYE DIAGRAM
Sample Index
Dire
ct
0 5 10 15 20 25 30 35-1
-0.5
0
0.5
1
Sample Index
Qua
drat
ute
Eye diagram
Semi-analytic Simulation (No ISI)Semi-analytic Simulation (No ISI)
04/21/23 16
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 100000
1
2
3
4
5
6
7
8
9Estimate of Noise Bandwidth of Receiver
Samples
Var
ianc
e E
stim
ate
at D
ecis
ion
Met
ric
Noise estimation
Semi-analytic Simulation (No ISI)Semi-analytic Simulation (No ISI)
04/21/23 17
-10 -8 -6 -4 -2 0 2 4 6 8 1010
-6
10-5
10-4
10-3
10-2
10-1
100
Ideal and Measured System Performance
SNR (Eb/No)
Bit
Err
or R
ate
Ideal BPSK
SA ResultBER vs SNR
Semi-analytic Simulation (with ISI)Semi-analytic Simulation (with ISI)
04/21/23 18
Delay Estimation
8 10 12 14 16 18 20 22
0.04
0.045
0.05
0.055
0.06
0.065
x-y
cros
scor
rela
tion
Computed Delay
Semi-analytic Simulation (with ISI)Semi-analytic Simulation (with ISI)
04/21/23 19
Eye diagram
0 5 10 15 20 25 30 35-20
-10
0
10
20D/Q EYE DIAGRAM
Sample Index
Dire
ct
0 5 10 15 20 25 30 35-1
-0.5
0
0.5
1
Sample Index
Qua
drat
ute
Semi-analytic Simulation (with ISI)Semi-analytic Simulation (with ISI)
04/21/23 20
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 100000
1
2
3
4
5
6
7
8
9Estimate of Noise Bandwidth of Receiver
Samples
Var
ianc
e E
stim
ate
at D
ecis
ion
Met
ric
Noise estimation
Semi-analytic Simulation (with ISI)Semi-analytic Simulation (with ISI)
04/21/23 21
BER vs SNR
-10 -8 -6 -4 -2 0 2 4 6 8 1010
-6
10-5
10-4
10-3
10-2
10-1
100
Ideal and Measured System Performance
SNR (Eb/No)
Bit
Err
or R
ate
Ideal BPSK
SA Result