Downlink MIMO Simulation for IEEE 802.16m
5.4 Simulation Results for Multipath Channels
Figs. 5.21–5.34 show the simulation with two transmit antennas and two receive antennas.
Figs. 5.21–5.25 show the MSE and SER with ZF equalizer and different feedback methods at different velocities and SNR values in Suburban channel. Figs. 5.26–5.27 show the per-formance of ZF equalizer with different feedback methods at velocities of 30 and 120 km/h.
We can see that MSE with ZF equalizer are relatively close in different feedback method.
This is because ZF equalizer can’t cancel the MSE.
Figs. 5.28–5.32 show the MSE and SER with MMSE equalizer and different feedback methods at different velocities and SNR values in Suburban channel.
Figs. 5.33–5.34 show the performance of different feedback methods at velocities of 30 and 120 km/h. We can see that both MSE and SER have the same curve. This is because the MMSE equalizer is finding the minimum mean square error and it also can be seem worked in SER. The optimum precoder method leads all the methods because it use the sounding method to transmit back the best precoder. Also both ZF and MMSE equalizer can achieve diversity one. We also compare all the methods in ZF and MMSE equalizer.
MMSE equalizer leads the ZF equalizer both in MSE and SER. This is because ZF equalizer has the noise enhancement problem.
Figs. 5.37–5.39 show the MSE and SER with ZF equalizer using 4 transmit antennas and 4 receive antennas. We can see that SER can achieve diversity order three.
Figs. 5.40–5.40 show the MSE and SER with ZF equalizer using different antennas and different feedback selection methods. We can see that 4 antennas outperforms 2 antennas.
And optimal precoder method with 4 antennas has more coding gain than 2 antennas.
0 5 10 15 20 25 30 10−1
100 101 102 103
ZF equalizer with No feedback
SNR (dB)
Normalize MSE
V 30 V 60 V 120 V 300
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10−3 10−2 10−1 100
ZF equalizer with no feedback
SNR (dB)
SER
V30 V60 V120 V300
Figure 5.21: MSE and SER for QPSK using ZF equalizer with no feedback in multipath 126
0 5 10 15 20 25 30 10−1
100 101 102 103
ZF equalizer with SVD−Based search feedback
SNR (dB)
Normalize MSE
V 30 V 60 V 120 V 300
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10−3 10−2 10−1 100
ZF equalizer with SVD−Based search feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.22: MSE and SER for QPSK using ZF equalizer with SVD-Based search feedback 127
0 5 10 15 20 25 30 10−1
100 101 102 103
ZF equalizer with MMSE−Based exhaustive search feedback
SNR (dB)
Normalize MSE
V 30 V 60 V 120 V 300
0 5 10 15 20 25 30
10−3 10−2 10−1 100
ZF equalizer with MMSE−Based exhaustive search feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.23: MSE and SER for QPSK using ZF equalizer with MMSE-Based exhaustive 128
0 5 10 15 20 25 30 10−1
100 101 102 103
ZF equalizer with MaxminSNR feedback
SNR (dB)
Normalize MSE
V 30 V 60 V 120 V 300
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10−3 10−2 10−1 100
ZF equalizer with MaxminSNR feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.24: MSE and SER for QPSK using ZF equalizer with MaxminSNR-Based search 129
0 5 10 15 20 25 30 10−1
100 101 102 103
ZF equalizer with Optimum Precoder feedback
SNR (dB)
Normalize MSE
V 30 V 60 V 120 V 300
0 5 10 15 20 25 30
10−3 10−2 10−1 100
ZF equalizer with Optimum precoder feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.25: MSE and SER for QPSK using ZF equalizer with Optimum precoder feedback 130
0 5 10 15 20 25 30 10−1
100 101 102 103
ZF equalizer with different feedback V30
SNR (dB)
Normalize MSE
No feedback ZF, SVD−Based ZF, MMSE−Based ZF, MaxminSNR ZF, Optimum Precoder
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10−3 10−2 10−1 100
ZF equalizer with different feedback V30
SNR (dB)
SER
No feedback ZF, SVD−Based ZF, MMSE−Based ZF, MaxminSNR ZF, Optimum Precoder
Figure 5.26: MSE and SER for QPSK using ZF equalizer with different feedback methods 131
0 5 10 15 20 25 30 10−1
100 101 102 103
ZF equalizer with different feedback V120
SNR (dB)
Normalize MSE
No feedback ZF, SVD−Based ZF, MMSE−Based ZF, MaxminSNR ZF, Optimum Precoder
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10−2 10−1 100
ZF equalizer with different feedback V120
SNR (dB)
SER
No feedback ZF, SVD−Based ZF, MMSE−Based ZF, MaxminSNR ZF, Optimum Precoder
Figure 5.27: MSE and SER for QPSK using ZF equalizer with different feedback methods 132
0 5 10 15 20 25 30 10−2
10−1 100 101
MMSE equalizer with no feedback
SNR (dB)
Normalize MSE
V30 V60 V120 V300
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10−3 10−2 10−1 100
MMSE equalizer with no feedback
SNR (dB)
SER
V30 V60 V120 V300
Figure 5.28: MSE and SER for QPSK using MMSE equalizer with no feedback in multipath 133
0 5 10 15 20 25 30 10−2
10−1 100 101
MMSE equalizer with SVD−Based feedback
SNR (dB)
Normalize MSE
V30 V60 V120 V300
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10−3 10−2 10−1 100
MMSE equalizer with SVD−Based feedback
SNR (dB)
SER
V30 V60 V120 V300
Figure 5.29: MSE and SER for QPSK using MMSE equalizer with SVD-Based search feed-134
0 5 10 15 20 25 30 10−2
10−1 100 101
MMSE equalizer with MMSE−Based exhaustive search feedback
SNR (dB)
Normalize MSE
V30 V60 V120 V300
0 5 10 15 20 25 30
10−3 10−2 10−1 100
MMSE equalizer with MMSE−Based exhaustive search feedback
SNR (dB)
SER
V30 V60 V120 V300
Figure 5.30: MSE and SER for QPSK using MMSE equalizer with MMSE-Based exhaustive 135
0 5 10 15 20 25 30 10−2
10−1 100 101
MMSE equalizer with MaxminSNR feedback
SNR (dB)
Normalize MSE
V30 V60 V120 V300
0 5 10 15 20 25 30
10−3 10−2 10−1 100
MMSE equalizer with MaxminSNR feedback
SNR (dB)
SER
V30 V60 V120 V300
Figure 5.31: MSE and SER for QPSK using MMSE equalizer with MaxminSNR-Based search 136
0 5 10 15 20 25 30 10−2
10−1 100 101
MMSE equalizer with Optimal precoder feedback
SNR (dB)
Normalize MSE
V30 V60 V120 V300
0 5 10 15 20 25 30
10−3 10−2 10−1 100
MMSE equalizer with Optimal precoder feedback
SNR (dB)
SER
V30 V60 V120 V300
Figure 5.32: MSE and SER for QPSK using MMSE equalizer with Optimum precoder 137
0 5 10 15 20 25 30 10−2
10−1 100 101
MMSE equalizer with different feedback in V30
SNR (dB)
Normalize MSE
No feedback MaxminSNR MMSE−Based SVD−Based Optimum precoder
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10−3 10−2 10−1 100
MMSE equalizer with different feedback in V30
SNR (dB)
SER
No feedback MaxminSNR MMSE−Based SVD−Based Optimum precoder
Figure 5.33: MSE and SER for QPSK using MMSE equalizer with different feedback methods 138
0 5 10 15 20 25 30 10−2
10−1 100 101
MMSE equalizer with different feedback in V120
SNR (dB)
Normalize MSE
No feedback MaxminSNR MMSE−Based SVD−Based Optimum precoder
0 5 10 15 20 25 30
10−3 10−2 10−1 100
MMSE equalizer with different feedback in V120
SNR (dB)
SER
No feedback MaxminSNR MMSE−Based SVD−Based Optimum precoder
Figure 5.34: MSE and SER for QPSK using MMSE equalizer with different feedback methods 139
0 5 10 15 20 25 30 10−2
10−1 100 101 102 103
Different equalizer with different feedback V30
SNR (dB)
Normalize MSE
ZF,,No feedback ZF, Codewordsearch ZF, MMSE Calculate ZF, MaxminSNR ZF, Optimum Precoder MMSE, No feedback MMSE, Codewordsearch MMSE, MMSE Calculate MMSE, MaxminSNR MMSE, Optimum Precoder
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10−3 10−2 10−1 100
Different equalizer with different feedback V30
SNR (dB) SER ZF, No feedback
ZF, SVD−Based ZF, MMSE−Based ZF, MaxminSNR ZF, Optimum Precoder MMSE, No feedback MMSE, SVD−Based MMSE, MMSE−Based MMSE, MaxminSNR MMSE, Optimum Precoder
Figure 5.35: MSE and SER for QPSK using ZF and MMSE equalizer with different feedback 140
0 5 10 15 20 25 30 10−2
10−1 100 101 102 103
Different equalizer with different feedback V120
SNR (dB)
Normalize MSE
ZF, No feedback ZF, SVD−Based ZF, MMSE−Based ZF, MaxminSNR ZF, Optimum Precoder MMSE, No feedback MMSE, SVD−Based MMSE, MMSE−Based MMSE, MaxminSNR MMSE, Optimum Precoder
0 5 10 15 20 25 30
10−3 10−2 10−1 100
Different equalizer with different feedback V120
SNR (dB) SER ZF, No feedback
ZF, SVD−Based ZF, MMSE−Based ZF, MaxminSNR ZF, Optimum Precoder MMSE, No feedback MMSE, SVD−Based MMSE, MMSE−Based MMSE, MaxminSNR MMSE, Optimum Precoder
Figure 5.36: MSE and SER for QPSK using ZF and MMSE equalizer with different feedback 141
0 5 10 15 20 25 30 10−3
10−2 10−1 100 101
ZF equalizer with SVD−based feedback
SNR (dB)
Normalize MSE
V 30 V 60 V 120 V 300
0 5 10 15 20 25 30
10−5 10−4 10−3 10−2 10−1 100
ZF equalizer with SVD−based feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.37: MSE and SER for QPSK using ZF equalizer with SVD-Based search feedback 142
0 5 10 15 20 25 30 10−2
10−1 100 101
ZF equalizer with MSE−based feedback
SNR (dB)
Normalize MSE
V 30 V 60 V 120 V 300
0 5 10 15 20 25 30
10−5 10−4 10−3 10−2 10−1 100
ZF equalizer with MSE−based feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.38: MSE and SER for QPSK using ZF equalizer with MMSE-Based exhaustive 143
0 5 10 15 20 25 30 10−3
10−2 10−1 100 101
ZF equalizer with optimal precoder feedback
SNR (dB)
Normalize MSE
V30 V60 V120 V300
0 5 10 15 20 25 30
10−7 10−6 10−5 10−4 10−3 10−2 10−1 100
ZF equalizer with optimal precoder feedback
SNR (dB)
SER
V30 V60 V120 V300
Figure 5.39: MSE and SER for QPSK using ZF equalizer with Optimum precoder feedback 144
0 5 10 15 20 25 30 10−3
10−2 10−1 100 101 102 103
ZF equalizer with different feedback V30
SNR (dB)
Normalize MSE
ZF, MMSE−Based 2*2 ZF, Optimum Precoder 2*2 ZF, MMSE−Based 4*4 ZF, Optimum Precoder 4*4
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10−6 10−5 10−4 10−3 10−2 10−1 100
ZF equalizer with different feedback V30
SNR (dB)
SER
ZF, MMSE−Based 2*2 ZF, Optimum Precoder 2*2 ZF, MMSE−Based 4*4 ZF, Optimum Precoder 4*4
Figure 5.40: MSE and SER for QPSK using ZF equalizer with different feedback methods 145
0 5 10 15 20 25 30 10−3
10−2 10−1 100 101 102 103
ZF equalizer with different feedback V120
SNR (dB)
Normalize MSE
ZF, MMSE−Based 2*2 ZF, Optimum Precoder 2*2 ZF, MMSE−Based 4*4 ZF, Optimum Precoder 4*4
0 5 10 15 20 25 30
10−6 10−5 10−4 10−3 10−2 10−1 100
ZF equalizer with different feedback V120
SNR (dB)
SER
ZF, MMSE−Based 2*2 ZF, Optimum Precoder 2*2 ZF, MMSE−Based 4*4 ZF, Optimum Precoder 4*4
Figure 5.41: MSE and SER for QPSK using ZF equalizer with different feedback methods 146