4
channel will be set to operate on the 914.4 MHz band with
a bandwidth of 100 kHz, while the communication chan-
nel will be set to the 915 MHz band, also with a bandwidth
of 100 kHz. Figure 2 illustrates a measurement of both the
interference signal and the communication signal within
the frequency spectrum, along with the background noise.
The communication packet size is configured as 64 bytes,
and the packet transmission rate is about 30 packets per
second. The throughput is about 15.5 Kbps. A known data
pattern is repeatedly transmitted through the channel and
the receiver will check each bit to calculate the bit error and
packet error. Each packet has a packet identification num-
ber. The number is increasing, allowing the receiving end to
accurately track which packets are correctly received, which
are received in error, and which are lost.
As shown in Table 3 and Figure 3, the bit error rate
(BER) increases exponentially with rising interference
power, suggesting that even slight increases in interference
or a decrease in signal power can lead to a significant increase
in errors. Additionally, the packet loss/error rate closely fol-
lows the trend of the BER, escalating as interference power
grows, as expected. This correlation means that as the BER
rises, the likelihood of packet errors increases substantially,
leading to more frequent communication failures. Notably,
when the bit error rate reaches approximately 0.00111, the
packet error rate spikes to 45.44%, indicating that nearly
half of all transmitted packets fail. This represents a criti-
cally high failure rate, severely compromising the reliability
of communication under such conditions. We also checked
the bit error pattern in the received packet and found the
following Table 4.
As Table 4 shows, the majority of errors in the pack-
ets consist of only one error bit, especially at lower levels
of interference power. However, as the interference power
increases, the number of error bits within each packet also
rises, which is evident from the increasing percentage of
2-bit errors. At interference power levels of 0.20 µW and
-120
-100
-80
-60
-40
-20
0
Frequency (MHz)
Communication
Signal at 915MHz
Background
Inteference Signal at
914.4MHz
Figure 2. Communication signal and interference signal in
the frequency domain
Table 3. Bit error rate and packet lost/error rate under
different interference power
Interference power
(µW)
0 0.20 0.40 0.63 1.26 2.51
Bit error rate(‱) 0 0 1.1 1.7 6.7 11.1
Packet loss/error
rate(%)
0 0.04 1.26 16.54 31.36 45.44
Note: The interference power is measured at the measurement
antenna by the spectrum analyzer. The bit error rate is calculated
by dividing the number of errored bits in the received packets
by the total number of bits in those packets. Additionally, the
packet loss/error rate is computed by calculating the ratio of
packets that were either lost or contained errored bits to the
total number of packets sent.
Table 4. Bit error pattern vs. interference
Interference power
(µW)
0 0.20 0.40 0.63 1.26 2.51
Bit error rate(‱) 0 0 1.1 1.7 6.7 11.1
Average error bit #0 0 1.02 1.08 1.11 1.39
1-bit error
percentage (%)
0 0 95 90.55 87.8 77.9
2-bit error
percentage (%)
0 0 4 8.52 10.28 18.89
Note: the average error bit #is calculated by taking the mean of
the number of errored bits across all packets containing errors.
The 1-bit error percentage is calculated by determining the
proportion of packets that contain exactly one errored bit out
of all errored packets. Similarly, the 2-bit error percentage is cal-
culated by determining the proportion of packets that contain
exactly two errored bits out of all errored packets.
0
10
20
30
40
50
0
3
6
9
12
0 1 2 3
Interference power (μW)
Packet error rate
Bit error rate
Figure 3. Bit error rate and packet error rate vs. interference
power
Spectrum
Power
(dBm)
Packet
error
rate
(%)
Bit
e
or
rate
(
)
channel will be set to operate on the 914.4 MHz band with
a bandwidth of 100 kHz, while the communication chan-
nel will be set to the 915 MHz band, also with a bandwidth
of 100 kHz. Figure 2 illustrates a measurement of both the
interference signal and the communication signal within
the frequency spectrum, along with the background noise.
The communication packet size is configured as 64 bytes,
and the packet transmission rate is about 30 packets per
second. The throughput is about 15.5 Kbps. A known data
pattern is repeatedly transmitted through the channel and
the receiver will check each bit to calculate the bit error and
packet error. Each packet has a packet identification num-
ber. The number is increasing, allowing the receiving end to
accurately track which packets are correctly received, which
are received in error, and which are lost.
As shown in Table 3 and Figure 3, the bit error rate
(BER) increases exponentially with rising interference
power, suggesting that even slight increases in interference
or a decrease in signal power can lead to a significant increase
in errors. Additionally, the packet loss/error rate closely fol-
lows the trend of the BER, escalating as interference power
grows, as expected. This correlation means that as the BER
rises, the likelihood of packet errors increases substantially,
leading to more frequent communication failures. Notably,
when the bit error rate reaches approximately 0.00111, the
packet error rate spikes to 45.44%, indicating that nearly
half of all transmitted packets fail. This represents a criti-
cally high failure rate, severely compromising the reliability
of communication under such conditions. We also checked
the bit error pattern in the received packet and found the
following Table 4.
As Table 4 shows, the majority of errors in the pack-
ets consist of only one error bit, especially at lower levels
of interference power. However, as the interference power
increases, the number of error bits within each packet also
rises, which is evident from the increasing percentage of
2-bit errors. At interference power levels of 0.20 µW and
-120
-100
-80
-60
-40
-20
0
Frequency (MHz)
Communication
Signal at 915MHz
Background
Inteference Signal at
914.4MHz
Figure 2. Communication signal and interference signal in
the frequency domain
Table 3. Bit error rate and packet lost/error rate under
different interference power
Interference power
(µW)
0 0.20 0.40 0.63 1.26 2.51
Bit error rate(‱) 0 0 1.1 1.7 6.7 11.1
Packet loss/error
rate(%)
0 0.04 1.26 16.54 31.36 45.44
Note: The interference power is measured at the measurement
antenna by the spectrum analyzer. The bit error rate is calculated
by dividing the number of errored bits in the received packets
by the total number of bits in those packets. Additionally, the
packet loss/error rate is computed by calculating the ratio of
packets that were either lost or contained errored bits to the
total number of packets sent.
Table 4. Bit error pattern vs. interference
Interference power
(µW)
0 0.20 0.40 0.63 1.26 2.51
Bit error rate(‱) 0 0 1.1 1.7 6.7 11.1
Average error bit #0 0 1.02 1.08 1.11 1.39
1-bit error
percentage (%)
0 0 95 90.55 87.8 77.9
2-bit error
percentage (%)
0 0 4 8.52 10.28 18.89
Note: the average error bit #is calculated by taking the mean of
the number of errored bits across all packets containing errors.
The 1-bit error percentage is calculated by determining the
proportion of packets that contain exactly one errored bit out
of all errored packets. Similarly, the 2-bit error percentage is cal-
culated by determining the proportion of packets that contain
exactly two errored bits out of all errored packets.
0
10
20
30
40
50
0
3
6
9
12
0 1 2 3
Interference power (μW)
Packet error rate
Bit error rate
Figure 3. Bit error rate and packet error rate vs. interference
power
Spectrum
Power
(dBm)
Packet
error
rate
(%)
Bit
e
or
rate
(
)