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Robert_Cuong

Wi-Fi installation and troubleshoot
Client Guide

WiFi Basic knowledge
2-3-2023

Wifi installation and troubleshoot

Contents
1

Purpose
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2

3

2
...
11 Standard
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2

About the 2
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2

2
...
3

2
...
3

ONT’s Wi-Fi installation
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1

4

5

3
...
1

Co-Channel interference
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1
...
4

3
...
3

Non-802
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5

3
...
5

3
...
6

3
...
6

Expanding Wi-Fi coverage/reach
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1

Wi-Fi Bridges
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2

Wireless Repeaters or Extenders
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8
5
...
8

5
...
1

Ping to some application server
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1
...
9

5
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4 GHz Interference Sources
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9

5
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1

Verifying the ONT’s position and Antenna orientation
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2
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11

5
...
3

Priority consideration
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12

Page 1 of 13

Version 1
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2 Introduction to Wi-Fi technology
2
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11 Standard



According to Wikipedia, "Wi-Fi, which stands for Wireless Fidelity or 802
...
4Ghz and 5GHz with the following basic
characteristics

2
...
4 GHz Wi-Fi Band




Wi-Fi (IEEE 802
...
4 GHz band
...
Normally
people will choose channels 1, 6 and 11 as shown below

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Version 1
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3 About the 5 GHz Wi-Fi Band




The 5 GHz frequency band has considerably more available spectrum than the 2
...
4 Antenna Characteristics



DASAN ONT use omnidirectional antenna with type of 5 dBi, which commonly used
indoors to provide coverage throughout an entire space
Devices directly above or below the omnidirectional antenna may have a
very weak signal or even be unable to detect the signal
...
1

Wifi installation and troubleshoot

3 ONT’s Wi-Fi installation
3
...
4 GHz Interference Sources
Most interference in wireless networks occurs in the 2
...
Follows is a partial
list of "interferers" and their relative effect on Wi-Fi signals

3
...
1 Co-Channel interference
 Whenever one transmitter’s signal overlaps another on a frequency or channel, the signals
interfere with each other
 Wireless LAN devices must contend for use of the airtime; if nobody is transmitting at a
given time, someone may use the channel
 When both transmitters are busy sending data, the channel can become very congested
...
1
...
However, the channels
are spaced too closely together such that they overlap each other




No one is taking turns, and the transmissions of each of the radios simply trample the
transmissions of the other
...
1

Wifi installation and troubleshoot


In some cases, even adjacent (non-overlapping) channels may cause
interference if the adjacent signals are high enough that the receiver filter cannot eliminate
the interference
3
...
3 Non-802
...
Many non-802
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2 Wi-Fi attenuation


Physical obstruction interferences

Page 5 of 13

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3 Instruction on installation of ONT


Place ONT in the central location of the house or as close to areas of wifi clients as
possible (living room, bedroom, office
...
11 interference devices as microwave ovens, wireless
mouse, speaker, TV, …
 Avoid some obstructions which make Wi-Fi signal loss much power as iron doors,
aluminum door frames, fish tanks, brick/concrete walls
...
5m high to get the strongest beam of Wi-Fi antenna
...
4 Instruction for installing anten angle


Antenna Angle = 900 helps the wave propagate in the
horizontal direction, it is suitable for homes with a floor
surface

Page 6 of 13

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1 Wi-Fi Bridges




House include a lot of floors, we can expand Wi-Fi coverage by adding Wireless access
point to ONT via LAN cable (CAT5)
Users typically enjoy increased performance, network simplicity, flexibility, control and
can easily add more access point
ONT can connect to Wan or Lan of access point:
 Via Wan: Lan’s network of access point which supply ip address to clients have
different subnet mask with Wan network
 Via Lan: ONT supply ip address to clients connecting to ONT or access point,
dhcp server of lan side of access point will be disable

4
...
The use of a second channel allows the repeater to receive and transmit
simultaneously and eliminates the halving of the bandwidth

Page 7 of 13

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1 Tools and techniques to indentify the Wi-Fi issues






To identify slow, unstable network due to Wi-Fi, use a laptop with two types of network
cards: Wi-Fi and LAN
To troubleshoot the internet problem, we have to find the problem come from where?
Including Wi-Fi clients? Environment ? ONT ? Uplink network ? or Application server ?
To get Wi-Fi interference, you should use some Wi-Fi application tool then take capture
of the environment
Download the log file of ONT, so that we can analyze if any potential problem come from
ONT
...

"System log" on the right and save as file:

Page 8 of 13

Version 1
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1
...
Then calculate the
average and record the test results (lost packet, average delay) in the following table:
LAN to ONT
A

LAN to Internet
B

Wifi to ONT
C

Wifi to Internet
D

 If A, B, C, D is almost equivalent: good network
 If A&B are equal, C&D is equivalent but A&B are much better than C&D: Need
to verify more about Wi-Fi part
 If both A&C are equal, B&D is equal but A&C is much better than B&D: Need to
verify the Uplink network
5
...
2 Wi-Fi network analyzer
 You can download and use some of the wifi analysis software as:
 Wifi analyze on android phone
https://play
...
com/store/apps/details?id=com
...
wifi
...
acrylicwifi
...
adriangranados
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2 Solution



To ensure the quality of the wifi signal, access points in the same area should run on
different wifi channels to avoid interference and congestion that affects the signal
Therefore, it is necessary to adjust the location of the AP and the Wi-Fi channel so that
received power ensure:
 The radius of cell should be better than -67 dBm
 The distance between two Access Points from the radius of the area Its coverage
is more than 19 dBm

Page 9 of 13

Version 1
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2
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If no
special condition, we should keep the factory default parameters
Because the antenna direction is not optimal:
 Adjusting the direction of the antenna can also help expand the Wi-Fi coverage
better
 Usually the antenna needs to be raised high with the antenna opening angle of 45º
Because the coverage area is too wide:
 An ONT can operate well with a distance of ≤ 10m or ≤ 20m without obstructions
 When need to use the internet via a Wi-Fi connection with a larger coverage area,
we should install an AP to expand the Wi-Fi coverage
Because the position of the ONT is not optimal:
 Most common position is to use one or two thick walls, through concrete
 In this case, it is necessary to move the AP to a frequently used position, try to
create a direct view from the AP to the location using wifi
...
1

Wifi installation and troubleshoot
 A small number of cases are due to placing APs near microwave ovens, coreless
phones and transmitters using 2
...
In this case, it is necessary
to move AP away from those devices
 Placing AP near large metal plates such as corrugated iron, corrugated walls also
affects signal quality
5
...
2 Checking the RF environment
 The noise and congestion of our Wi-Fi signal is usually due to the ONT being placed in
an environment with multiple operating APs or having other non-802
...
So you
need to bring your ONT to the best channel possible to resolve the immediate error
...
As above cases you can switch your ONT operating on channel 6
(congested) or 9 (jamming) to channel 1
 Adjust the optimal configuration, frequency planning for APs in the same area
avoid frequency overlap
...
4Ghz from 40Mhz to 20Mhz
...
However, in an environment with many AP
operations
...
This helps to ensure the quality of services provided as well
as reduce the load for the Wi-Fi system, reserved bandwidth for devices with WiFi connection such as smart phones
 Use Wi-Fi frequency 5Ghz for devices that support standard 5Ghz
...
4Ghz frequency, only 3 signal channels do not
overlap but Wi-Fi network operating at 5Ghz frequency has up to 23 signal
channels not overlap so Wi-Fi system also better data transmission, thus can
improve the quality of service and reduce the load on the overloaded 2
...
1

Wifi installation and troubleshoot
5
...
3 Priority consideration
In fact, we have no control over all Access Points that are running in the area
...
So we need to sequentially implement
the most effective, most cost-effective options as follows:
Option 1
...
) to use
LAN cable
...

When coverage is not guaranteed, an additional Access Point is
required
...

Move our Access Points to run on the best wifi channel in the area
...

Deploy another Access Point running in 5GHz band in case all 3
channels of WiFi 1, 6 and 11 have unsatisfactory results
...
4Ghz and some older phones do not support it
...

If possible, you should contact all network administrators in the
planning area, redistribute the frequency and location of Access Points
so that they are optimal
...
1

Wifi installation and troubleshoot
PHY
PIFS
PLCP
PPDU
ppm
PSD
PSDU
PSMP
PSMP-DTT
PSMP-UTT
QAM
QoS
QPSK
R
RA
RD
RDG
RF
RIFS
RMS
RSSI
RTS
Rx
SA
SAP
SCP
SDM
SDU
SE
SIFS
SIG
SIMO
SISO
SMTP
SNR
SOHO
SS
SSC
SSID
SSN
STA
STBC
STF
STS

Page 13 of 13

physical layer
PCF inter-frame space
physical layer convergence procedure
PLCP protocol data unit
parts per million
power spectral density
PLCP service data unit
power-save multi-poll
PSMP downlink transmission time
PSMP uplink transmission time
quadrature amplitude modulation
quality of service
quadrature phase shift keying
code rate
receiver address
reverse direction
reverse direction grant
radio frequency
reduced inter-frame space
root-mean-square
received signal strength indication
request to send
receive
source address
service access point
secure copy protocol
spatial division multiplexing
service data unit
spatial expansion
short inter-frame space
Signal field
single-input, multiple-output
single-input, single-output
simple mail transfer protocol
signal-to-noise ratio
small-office, home-office
spatial stream
starting sequence control
service set identifier
starting sequence number
station
space-time block coding
Short Training field
space-time stream

Version 1

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