This paper proposes a new Wi-Fi signal quality indicator that combines measured received signal strength indicator (RSSI) values with performance measures like latency and packet loss to more accurately predict signal quality. The current indicator of RSSI value alone can mislead users because factors like interference may affect performance even when RSSI is high. An experiment showed network performance was poor despite a high RSSI value during microwave interference. The proposed indicator considers both RSSI and performance to give users a better understanding of their actual Wi-Fi experience.

1. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
ISBN: 978 0 994365644
www.apiar.org.au
IMPROVED WI-FI SIGNAL QUALITY
INDICATOR USING WI-FI PERFORMANCE
OBSERVATION
Ahmad Tajuddin Samsudin, Mohd Shahril Saharedan,
Syaiful Nizam Yahya, Mohd Syafarees Ishak, Siti Salwa Said
Computational Sciences, Telekom Research & Development, Cyberjaya, Malaysia
Corresponding email: tajuddin@tmrnd.com.my

2. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
What is your choice?
A B C D
INTRODUCTION
) signal quality
in Wi-Fi connectivity
The majority of people will
tend to choose a full bar
((A)) to make an Internet
connection
But the signal quality
will not guarantee the
best Internet
experience

3. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
PERCEPTION
Typical perception in Wi-Fi :
High RSSI value = excellent Wi-Fi
performance
The perception not
always true :
can be denied by
radio frequency
disturbance from
electromagnetic
signals, congested
frequency and
congested traffic
Is your RSSI misleading you?
Excellent (above -56dBm) ; Good (between -55dBm & -69dBm) ; Poor (lower -68dBm)

4. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
INTERFERENCE

5. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
This paper proposed a new indicator and method to
determine the actual performance of received Wi-Fi signal.
Measured RSSI combined with Wi-Fi performance measures
(latency, loss) = predicted RSSI
SOLUTION
Customer can monitor the Wi-Fi performance against the actual
signal strength received by the device.

6. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
HYPOTHESES
Hypotheses:
(i) Hypothesis null 1 (H1) — there is no correlation between the RSSI and latency
(ii) Hypothesis null 2 (H2) — there is no correlation between the RSSI and packet loss

7. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
HYPOTHESES NULL REJECTED
Hypotheses: H1 & H2
The ANOVA regression analysis
of Figures 5(b) and 6(b)
showed that the Significance
value was 0.000 for both
regression analyses between
RSSI and latency, and RSSI
with packet loss. Since the p
value was lower than 0.05, we
rejected hypotheses H1 and H2.
We can conclude that there is
significant correlation
between the RSSI and latency
as well as RSSI and packet
loss.

8. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
EXPONENTIAL MODEL
From Figures 5(a) and 6(a), we plotted the exponential model:
y = e ^ (x.RSSI + Ln (Constant)) (1)
Exponential model for RSSI and Latency
x = (Ln(y) - 1.694)/(-0.012) (3)
Exponential model for RSSI and Loss
x = (Ln(y) + 16.186)/(-0.218) (4)
For example:
 If we want the x value corresponding to latency (y = 10 ms), using the above
model (3), we get x = (Ln 10 - 1.694) /(-0.012) = −50.72 dBm.
 If we want to predict the x value corresponding to packet loss (0.01%), using
the model (4), we get x = (Ln (0.01) + 16.186) /(-0.218) = −53.12dBm.

9. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
EXPERIMENT - SIGNAL INDICATOR
To prove that the signal quality indicator shown in Figure 1 may
mislead Wi-Fi customers, we conducted a simple experiment to show
that the full bar of the signal quality indicator [Figure 1(a)] is not
necessarily a good indicator of network performance.
This experiment was conducted in a controlled space of 10x10 meters.
Generally, we wanted to show the differences in Wi-Fi signal quality
and performance when using IEEE 802.11n technology where the
electromagnetic signal was generated to interfere with the connection
established between the device and the AP.

10. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
EXPERIMENT - RESULT
Condition 1 – microwave oven off
Condition 2 – microwave oven on
Condition 3 – microwave oven off

11. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
EXPERIMENT - DISCUSSION
RSSI in all three conditions is consistent and above -50dBm. These findings show
that the RSSI received by the laptop was not affected by the electromagnetic signal
produced by the microwave oven.
In Condition test 2 (Microwave ON), the customer knows that the Wi-Fi receiver
for the laptop and RG antenna works well because the actual RSSI is high, but the
indicator for Wi-Fi performance is one bar. This means that there are some issues
with Wi-Fi performance.

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5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
WHAT IS YOUR CHOICE?
A B C D
E F G H

13. TM Research & Development
5th Asia Pasific Conference on Advanced Research (APCAR, April 2017)
SUMMARY
RSSI value does misleads users sometimes.
There are factors that are not visible that disrupts
Wi-Fi signal.
The suggested indicator in this paper could
prompt the user minimize/eradicate unknown
interference source.

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THANK YOU
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