coexistence of li fi and wifi

COEXISTENCE OF LiFi & WiFiConcepts, Opportunities,

Challenges

Presented by, Riya Josh

S7 A ; 45Under the guidance of,

Mrs. Sophia Susan John

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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

OVERVIEW

College Of Engineering Chengannur

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Supporting UDs mobility LiFi Transceivers Performance of indoor and outdoor links Comparison of three systems Applications Future Scope Conclusion Reference


OVERVIEW (contd…)

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Increasing demand of network.

Increasing Wireless HetNets.

Independent existence of VLC and WiFi.

What if they coexist?????

INTRODUCTION


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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

WHAT IS WiFi???


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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.

WHAT IS LiFi????


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COMPARISONWiFi 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.


8College Of Engineering Chengannur

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Slow connectivity

Action of CSMA/CA.

PRIMARY CHALLENGES OF PRESENT WIRELESS COMMUNICATION


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WHY WiFi AND LiFi TOGETHER ?

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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How user devices are attached to the n/w?

How mobility of the device is supported?

How multiple users are accommodated?

CHALLENGES ON INCORPORATING LiFi AND WiFi


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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.

LINKING UDs TO NETWORK


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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

SUPPORTING UDs MOBILITY


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LiFi TRANSCEIVERS In todays world there are LiFi receivers but

not transmitters.


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A Proposed Model Of LiFi Transceiver


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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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PERFORMANCE OF INDOOR AND OUTDOOR LINKSVERTICAL DISTANCE BETWEEN THE LIFI TRANCEIVER AND THE UDs


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HORIZONTAL DISTANCE BETWEEN THE LIFI TRANCEIVER AND THE UDs


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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.

COMPARISON OF THREE SYSTEMS


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Hybrid System Aggregate system


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THROUGH PUT V/S DISTANCE


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THROUGHPUT V/S BLOCKAGE DURATION


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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.

APPLICATIONS


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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.

FUTURE


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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.

CONCLUSION


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REFERENCES


[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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THANK YOU……..
