72
3 Physical Theory of RFID System Physical Anti-Collision
Table 3.2 Prediction
evaluation parameters of the
model equation
r p
0.9538
SEP
0.0229
Fig. 3.9 Scatter diagram of prediction reading distance
reading distance and the corrected correlation coefficient is significant. And the
standard error of prediction SEP has a very small value. From Table 3.2, we can
see that the error range of the measurement is within ±3% and the main reason
is that different temperature have a slight influence on reflecting and absorbing an
electromagnetic wave of the plastic box.
In practice, wireless communication channels are subject to channel impairments
such as fading in addition to additive noise. Similarly, the reading distance of tags
is greatly influenced by the noise in the channel, particularly fading, which could
cause frequency offset [16]. In the case of frequency offset, the influence of fading on
reading distance could be given via replacing f
with f
= (f
+
) in Eq. (3.13), in
which
is the offset of working frequency. This work is in the presence of assuming
no fading to consider the effects of temperature on the reading performance of tags
at low speed in the indoor environment.
3 Physical Theory of RFID System Physical Anti-Collision
Table 3.2 Prediction
evaluation parameters of the
model equation
r p
0.9538
SEP
0.0229
Fig. 3.9 Scatter diagram of prediction reading distance
reading distance and the corrected correlation coefficient is significant. And the
standard error of prediction SEP has a very small value. From Table 3.2, we can
see that the error range of the measurement is within ±3% and the main reason
is that different temperature have a slight influence on reflecting and absorbing an
electromagnetic wave of the plastic box.
In practice, wireless communication channels are subject to channel impairments
such as fading in addition to additive noise. Similarly, the reading distance of tags
is greatly influenced by the noise in the channel, particularly fading, which could
cause frequency offset [16]. In the case of frequency offset, the influence of fading on
reading distance could be given via replacing f
with f
= (f
+
) in Eq. (3.13), in
which
is the offset of working frequency. This work is in the presence of assuming
no fading to consider the effects of temperature on the reading performance of tags
at low speed in the indoor environment.