Biomedical Engineering Reference
In-Depth Information
Table 6
Diversity parameters for five different links at eight different locations in an indoor
environment with a spacing of 0.34
λ
0
between receiver (Rx) antenna
Links
Results
Location number in an indoor environment
1
2
3
4
5
6
7
8
Chest
MRC (dB)
11.92
12
12.16
12.04
12.29
13.28
13.5
12.58
EGC (dB)
10.63
10.79
10.56
10.83
11.23
12.14
12.29
11.44
SC (dB)
9.79
9.93
9.78
10.05
10.47
11.28
11.27
10.76
0.065
0.061
0.070
0.054
0.029
0.031
0.040
ρ
e
Imbalance (dB)
3.09
3.08
2.98
2.96
2.59
2.29
2.24
2.36
Head
MRC (dB)
13.08
12.67
12.94
12.26
13.1
12.69
12.18
13.22
EGC (dB)
11.97
11.61
11.93
11.33
12.49
12.24
11.66
11.93
SC (dB)
11.12
10.9
11.23
10.57
11.89
11.5
10.62
11.25
ρ
e
0.071
0.067
0.065
0.056
0.057
0.073
0.072
0.057
Imbalance (dB)
2.39
2.51
2.51
2.53
2.06
2.23
2.41
1.65
Wrist
MRC (dB)
11.12
11.90
11.47
11.36
11.60
11.11
11.38
10.87
EGC (dB)
10.23
11.03
10.51
10.66
10.56
10.21
10.7
10.08
SC (dB)
9.64
10.39
10.02
10.03
9.90
9.45
9.96
9.48
ρ
e
0.080
0.085
0.078
0.082
0.081
0.082
0.082
0.097
Imbalance (dB)
4.03
4.03
4.03
4.06
4.01
4.03
3.99
3.93
Ankle
MRC (dB)
11.23
11
10.81
11.13
10.83
12.27
11.58
10.97
EGC (dB)
10.22
10.44
10.15
10.89
10.35
11.98
11.02
10.48
SC (dB)
9.79
10.04
9.72
10.49
10.03
11.38
10.89
10.21
ρ
e
0.121
0.114
0.114
0.120
0.113
0.123
0.147
0.134
Imbalance (dB)
4.34
4.63
4.56
4.57
4.43
4.13
3.86
4.49
Back
MRC (dB)
14.28
14.42
14.25
14.4
14.13
13.28
13.76
13.58
EGC (dB)
12.63
12.70
12.95
12.86
11.80
12.39
12.44
11.23
SC (dB)
11.72
11.85
12.12
12.10
11.86
11.65
11.59
11.23
ρ
e
0.033
0.030
0.0356
0.039
0.0357 0.0359
0.041
0.048
Imbalance (dB)
1.60
1.54
1.48
1.84
1.68
2.03
1.99
1.88
EGC
equal-gain combining,
MRC
maximum-ratio combining,
SC
selection combining
Diversity Branch Spacing Versus Diversity Parameters
Table
7
lists the DG values using different combining techniques, envelope correla-
tion coefficient (
ρ
e
) and the power imbalance between the two branches for the five
on-body channels for different spacing between diversity branch antennas in the in-
door environment at location 2 (location 2 is shown in Fig.
3
). It can be noticed from
the Table
7
that almost for all the channels the correlation between the diversity branch
signals is lower at 0.48
λ
0
as compared to 0.34
λ
0
, as is the case for on-body and this is
due to an increase in the power imbalance for 0.48
λ
0
case that reduces the DG slightly.
Thus, 0.34
λ
0
spacing is a good choice due to compactness of diversity antennas and
relatively high DG. This spacing gives similar performance as the highest spac-
ing possible and also as described in “Mutual Coupling Between Diversity Branch
Antennas”, the mutual coupling remains below
−
15 dB for all links at this spacing.
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