The upcoming technology of coexistence of LiFi and WiFi is a promising area of research and studies. Uplink via LiFi is the major challenge

1. Concepts, Opportunities, Challenges
Presented by,
Riya Josh
S7 A ; 45
Under the guidance of,
Mrs. Sophia Susan John

2.  Introduction
 What is WiFi ?
 What is LiFi ?
 Comparison
 Primary challenges of present wireless
communication.
 Why LiFi and WiFi together ?
 Challenges on incorporating LiFi and WiFi
 Linking UDs to network
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3.  Supporting UDs mobility
 LiFi Transceivers
 Performance of indoor and outdoor links
 Comparison of three systems
 Applications
 Future Scope
 Conclusion
 Reference
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4.  Increasing demand of network.
 Increasing Wireless HetNets.
 Independent existence of VLC and WiFi.
 What if they coexist?????
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5.  WiFi is a technology that allows electronic
devices to connect to a wireless LAN.
 WiFi is less secure than wired connections.
 Its demerits include Interference, limited
range and high power consumption
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6.  Li-Fi is a Visible Light Communications
system running wireless communications
travelling at very high speeds.
 LED bulb that varies its intensity faster than a
human eye can follow.
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7. WiFi LiFi
 Speed is about
54Mb/s.
 Use radio waves as
carrier.
 Less secure.
 LOS is not required.
 Speed is greater than
1Gb/s.
 Use visible light
communication.
 Highly secure.
 LOS is highly required.
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9.  Slow connectivity
 Action of CSMA/CA.
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10.  80% mobile users are indoor users
 LiFi enabled indoor lights modeled as optical-SCs.
 Today LiFi enables ONLY downlink. Uplink is still a challenge .
 Provides High-speed traffic offloading and security enhancement.
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12.  How user devices are attached to the n/w?
 How mobility of the device is supported?
 How multiple users are accommodated?
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13.  More than one luminaire at a sight.
 CSI : Channel State Information
 It is advantage whenever high through-put is
required.
 Three possible scenarios:
1. Single user provided with single luminaire.
2. Single user provided with multiple luminaires.
3. Multiple users provided with multiple luminaires.
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14.  Maintaining connectivity for the mobile users
is the primary challenge.
 Handover mechanism the traffic from a UD is
rerouted from O-SCs to RF-SCs and vice
versa.
 Other mechanism: OFDMA
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15.  In todays world there are LiFi receivers but
not transmitters.
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17.  Si PIN photodiode to provide high speed.
 Plano-convex 1”lens are used to concentrate
the beam and enlarge the receiving area.
 BBU is used to convert Ethernet packets into
DC-biased OFDM signals.
 Channel quality and illumination level are the
factors that affects the data rate.
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20. 1. Only WiFi is used to connect to internet.
2. Hybrid system – WiFi is used to connect the
downlink and uplink along with LiFi as
downlink.
3. Aggregate system – user is connected via
both LiFi and WiFi system.
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21. Hybrid System Aggregate system
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24.  Health sector: Since WiFi alone is not safe to
be used in hospitals.
 Internet anywhere: street lamps, light of
vehicles can be used to access internet
anywhere in footpaths, roads, malls,
anywhere where light source is available.
 IoT : Internet of things.
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25.  Further evolution of LiFi and WiFi to higher
data rates.
 Coexistence and further evolution of
CSMA/CA and OFDMA.
 Physical layer techniques to enhance the user
mobility.
 Improvement and development of the
existing optical front ends.
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26.  Coexistence between LiFi and WiFi is a new
promising research area.
 Improved techniques to enable high speed
offloading.
 Both technologies together gives triple
throughput for individual users.
 There is a great deal of research opportunity for
LiFi+WiFi network.
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[1] Moussa Ayyash, Hany Elgala, Abdallah Khreishah,
“Coexistence of WiFi and LiFi Toward 5G:
Concepts, Opportunities, and Challenges”, IEEE
Communications Magazine, Year: 2016, Volume:
54, Issue: 2,Pages: 64 - 71
[2] Harald Haas; Liang Yin; Yunlu Wang; Cheng Chen, “What
is LiFi? ”Journal of Light wave Technology, Year:
2016, Volume: 34, Issue: 6,Pages: 1533 - 1544

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