Downlink MIMO Simulation for IEEE 802.16m
5.3 Simulation Results for Single-Path Channels
Figs. 5.5–5.9 show the MSE and SER with ZF equalizer and different feedback methods at different velocities and SNR values in Suburban channel. Figs. 5.10–5.11 show the perfor-mance 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 not cancel the MSE.
Figs. 5.12–5.16 show the MSE and SER with MMSE equalizer and different feedback methods at different velocities and SNR values in Suburban channel.
Figs. 5.17–5.18 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. 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. Also both ZF and MMSE equalizer can achieve diversity one. We can see in the SER simulation that ZF equalizer with Optimum precoder has better performance in low SNR and MMSE equalizer with Optimum precoder has better performance in high SNR.
0 2 4 6 8 10 12 10−3
10−2 10−1 100
SNR (dB)
Normalize MSE
MMSE Equalizer ZF Equalizer
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SER
MMSE Equalizer ZF Equalizer AWGN
Figure 5.4: MSE and SER for QPSK resulting from simulation compared with theory in 108
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10−1 100 101 102
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
V 30 V 60 V 120 V 300
Figure 5.5: MSE and SER for QPSK using ZF equalizer with no feedback in Suburban 109
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10−1 100 101 102
ZF equalizer with SVD−Based 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 feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.6: MSE and SER for QPSK using ZF equalizer with SVD-Based search feedback 110
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10−1 100 101 102
ZF equalizer with MSE−Based feedback
SNR (dB)
Normalize MSE
V 30 V 60 V 120 V 300
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ZF equalizer with MSE−Based feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.7: MSE and SER for QPSK using ZF equalizer with MMSE-Based exhaustive 111
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10−1 100 101 102
ZF equalizer with MaxminSNR−Based feedback
SNR (dB)
Normalize MSE
V 30 V 60 V 120 V 300
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ZF equalizer with MaxminSNR−Based feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.8: MSE and SER for QPSK using ZF equalizer with MaxminSNR-Based search 112
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10−1 100 101 102
ZF equalizer with Optimum precoder−Based feedback
SNR (dB)
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V 30 V 60 V 120 V 300
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10−3 10−2 10−1 100
ZF equalizer with Optimum precoder−Based feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.9: MSE and SER for QPSK using ZF equalizer with Optimum precoder feedback 113
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100 101 102 103
ZF equalizer with different feedback V30
SNR (dB)
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No feedback Codewordsearch MMSE Calculate MaxminSNR Optimum Precoder
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ZF equalizer with different feedback V30
SNR (dB)
SER
No feedback Codewordsearch MMSE Calculate MaxminSNR Optimum Precoder
Figure 5.10: MSE and SER for QPSK using ZF equalizer with different feedback methods 114
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100 101 102 103
ZF equalizer with different feedback V120
SNR (dB)
Normalize MSE
No feedback SVD−Based MMSE−Based MaxminSNR Optimum Precoder
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ZF equalizer with different feedback V120
SNR (dB)
SER
No feedback SVD−Based MMSE−Based MaxminSNR Optimum Precoder
Figure 5.11: MSE and SER for QPSK using ZF equalizer with different feedback methods 115
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10−1 100
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 5.12: MSE and SER for QPSK using MMSE equalizer with no feedback in Suburban 116
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10−1 100
MMSE equalizer with SVD−Based search 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 search feedback
SNR (dB)
SER
V30 V60 V120 V300
Figure 5.13: MSE and SER for QPSK using MMSE equalizer with SVD-Based search feed-117
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10−1 100
MMSE equalizer with MMSE−Based exhaustive search feedback
SNR (dB)
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V 30 V 60 V 120 V 300
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10−3 10−2 10−1 100
MMSE equalizer with MMSE−Based exhaustive search feedback
SNR (dB)
SER
V 30 V 60 V 120 V 300
Figure 5.14: MSE and SER for QPSK using MMSE equalizer with MMSE-Based exhaustive 118
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10−2 10−1 100
MMSE 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
MMSE equalizer with MaxminSNR feedback
SNR (dB)
SER
V30 V60 V120 V300
Figure 5.15: MSE and SER for QPSK using MMSE equalizer with MaxminSNR-Based search 119
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10−2 10−1 100
MMSE equalizer with Optimal precoder feedback
SNR (dB)
Normalize MSE
V30 V60 V120 V300
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10−3 10−2 10−1 100
MMSE equalizer with Optimal precoder feedback
SNR (dB)
SER
V30 V60 V120 V300
Figure 5.16: MSE and SER for QPSK using MMSE equalizer with Optimum precoder 120
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10−2 10−1 100
MMSE equalizer with different feedback V30
SNR (dB)
Normalize MSE
MMSE, No feedback MMSE, Codewordsearch MMSE, MMSE Calculate MMSE, MaxminSNR MMSE, Optimum Precoder
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MMSE equalizer with different feedback V30
SNR (dB)
SER
MMSE, No feedback MMSE, Codewordsearch MMSE, MMSE Calculate MMSE, MaxminSNR MMSE, Optimum Precoder
Figure 5.17: MSE and SER for QPSK using MMSE equalizer with different feedback methods 121
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10−1 100
MMSE equalizer with different feedback V120
SNR (dB)
Normalize MSE
MMSE, No feedback MMSE, Codewordsearch MMSE, MMSE Calculate MMSE, MaxminSNR MMSE, Optimum Precoder
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10−3 10−2 10−1 100
MMSE equalizer with different feedback V120
SNR (dB)
SER
MMSE, No feedback MMSE, Codewordsearch MMSE, MMSE Calculate MMSE, MaxminSNR MMSE, Optimum Precoder
Figure 5.18: MSE and SER for QPSK using MMSE equalizer with different feedback methods 122
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10−2 10−1 100 101 102
Different equalizer with different feedback V30
SNR (dB)
Normalize MSE
ZF,,No feedback ZF, SVD−Based ZF, MSE−Based
ZF, MaxminSNR−Based ZF, Optimum Precoder−Based MMSE, No feedback
MMSE, SVD−Based MMSE, MSE−Based
MMSE, MaxminSNR−Based MMSE, Optimum Precoder−Based
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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, MSE−Based
ZF, MaxminSNR−Based ZF, Optimum Precoder−Based MMSE, No feedback
MMSE, SVD−Based MMSE, MSE−Based
MMSE, MaxminSNR−Based MMSE, Optimum Precoder−Based
Figure 5.19: MSE and SER for QPSK using ZF and MMSE equalizer with different feedback 123
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10−1 100 101 102
Different equalizer with different feedback V120
SNR (dB)
Normalize MSE
ZF,,No feedback ZF, SVD−Based ZF, MSE−Based
ZF, MaxminSNR−Based ZF, Optimum Precoder−Based MMSE, No feedback
MMSE, SVD−Based MMSE, MSE−Based
MMSE, MaxminSNR−Based MMSE, Optimum Precoder−Based
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10−3 10−2 10−1 100
Different equalizer with different feedback V120
SNR (dB) SER ZF,,No feedback
ZF, SVD−Based ZF, MSE−Based
ZF, MaxminSNR−Based ZF, Optimum Precoder−Based MMSE, No feedback
MMSE, SVD−Based MMSE, MSE−Based
MMSE, MaxminSNR−Based MMSE, Optimum Precoder−Based
Figure 5.20: MSE and SER for QPSK using ZF and MMSE equalizer with different feedback 124