Light Communication (LiFi) for FTTx Solutions – Enabling last-mile broadband connectivity

Internet services started with a dial-up connection that offered download speed of less than 100kbit/second. With time the faster internet technologies such as Digital Subscriber Lines (DSL) and cable modems were introduced. With the introduction and improvement of new technologies, the companies came up with services which can make use of increased speed offering and at the same time start introducing futuristic services and applications which demanded more bandwidth. Presently the most widespread wireline networks are DSL, cable modems and FTTx. Out of these three wireline services, FTTx using OFC cables offer the highest internet speed which can range from 1 Mbps to 1 Gbps. 

Internet Service Providers (ISPs), purchases international bandwidth based on the expected traffic from international bandwidth providers who own submarine cable infrastructure. They further purchase the required amount of inter-city bandwidth catered by OFC infrastructure owners to connect the international gateway to specific cities. Within a city ISPs either lay their own OFC infrastructure or purchase capacity from independent infrastructure owners. The final leg involves last mile connectivity which is provided via underground or overhead cables. In the case of FTTx, Optical Fibre Cables are used in last-mile connectivity to provide high-speed internet services.  

The overall costs of Right of Way (RoW) both at the intra-city level and then last-mile connectivity to the subscribers’ location have made wired ISP networks costly and in quite a few locations laying of OFC infrastructure is unfeasible or uneconomic. The cost of RoW has been the most important issue that has been preventing the growth of FTTx subscribers. The companies require approvals from municipalities & local/private bodies for laying cables. The approval procedures are cumbersome and time-consuming and municipalities generally approve digging operations during a limited time of a day. This has prevented the widespread rollout of services even in big metros. Further, the costs of such approvals are prohibitive. Due to these issues, most ISPs face a challenge in serving end consumers both retail as well as enterprises (except big enterprises whereby the CAPEX and OPEX cost can be justified) through a wireline network. 

The current use of OTT platforms for entertainment in homes & cloud-based services for businesses has increased the scope of FTTx solutions exponentially. IoT, gaming and video streaming required high internet bandwidth which is propelling the demand for increased bandwidth. The ISPs are finding it hard to keep up with the demand due to issues in laying new OFC infrastructure. The current status of the FTTx market in many developing countries can easily be compared to the introduction of DSL and cable modems. Penetration levels of wired broadband i.e. FTTx are minuscule in developing countries as compared to developed economies and there are several fundamental factors that will propel penetration levels near-global standards.

As can be seen from the data presented in the following table, the growth in wired broadband subscribers is subdued due to high CAPEX involved in connecting new homes. But due to the low base and customers’ preference for high-speed internet, fiber-based connections have increased at a rate of ~80% during the last five years. It is expected that this increase in demand will continue in future as well and with introduction of Light Communication ( LiFi ) as last-mile connectivity will provide a much-needed push for FTTx since the fiber connection to the node is already available at certain locations but connecting each and every household or building via fiber to those nodes is inefficient and uneconomical. 


(in millions) Mar-15 Mar-16 Mar-17 Mar-18 Mar-19 CAGR
Wired Broadband Subscribers (A) 15.52 16.98 18.24 17.95 18.42 4%
Fiber (B) 0.13 0.24 0.39 0.65 1.35 80%
(=B/A) 0.8% 1.4% 2.1% 3.6% 7.3%  
Enterprises -leased lines ( C)   0.06 0.09 0.11 0.14 33%
(=C/A)   0.4% 0.5% 0.6% 0.8%  

Reference: TRAI data


Light Communication (LiFi) based Optical Wireless Backhaul for FTTx 

The use of Light Communication (LiFi) will considerably reduce the inefficiencies and costs incurred in providing FTTx. Though Light Communication is most suitable for last-mile connectivity, it can also be implemented for connectivity within a city by using street lamp post for optical wireless communication. In addition to the difficulty in laying OFC based infrastructure, the merits of Light Communication such as high speed, huge bandwidth, and low cost should make it a preferred choice for last-mile connectivity in due future. 

Radio frequency based as a backhaul solution has been used but not with much success as the radio signals have limited bandwidth and high propagation & nodal data loss. With the use of Light Communication, these limitations can be overcome. Additionally, microcell architecture shall considerably reduce the cost of passive elements such as energy consumption, generators, batteries, etc. compared to a macro-cell architecture. 

Velmenni’s optical wireless backhaul technology can support the FTTx network in places where there is a challenge to lay the OFC till the home or enterprise location. This technology can also reduce time to market as laying OFC is always time taking at critical locations and sometimes impossible too. Such cases can be addressed directly by Velmenni wherein Light Communication based wireless link nodes can be installed at a location of fiber availability and from there a wireless link can be established to the home/enterprise location where the other Light Communication node will be placed. 

Optical wireless backhaul solution for FTTx can deliver the following:

  • Throughput (Up-to 1 Gbps) 
  • Distance between wireless links (Up-to 200 meters)

Light Communication as a part of 5G and beyond

Light communications as a part of 5G

Light communications as a part of 5G

The world is quickly reaching a threshold in data connectivity, and the demand for it is outgrowing the supply of wireless bandwidth. LiFi is a new technology that can leverage light to create billions of connections.

As more people, devices and services compete for limited radio spectrum — 3G, 4G, 5G, Wi-Fi, Bluetooth, digital radio, and TV, the world of data communication is running out of spectrum through which it communicates.

According to a study conducted by Nokia Bell Labs, The World’s demand for wireless data will be outrun by 30% by 2020.

A study by Ericsson shows that mobile data is growing at 60% per year to 71 exabytes per month — or 71 billion bytes — by 2021. Around 90% of mobile data will be consumed indoors by 2022, and connected devices in our homes are foreseen to increase from 10 devices today to 50 in just 5 years. This growth will cause congestion in our radio spectrum and will create the risk of not meeting our demands drastically.

Privacy and security have also become a growing concern amongst consumers and enterprise customers alike. Those who operate these wireless networks end up facing a constant challenge of ensuring wide coverage and its protection.

LiFi, considered as a potential medium for 5G wireless communications, is gaining popularity in multiple industries. LiFi has strengths in energy efficiency and ultra-wide bandwidth. At the same time, being a fairly new technology, it’s still steadily growing in transmission range and overcoming obstacles in transmission paths. This article aims to provide a conclusive investigation of the latest progress in research and development on LiFi, which can be highly advantageous when made a part of 5G wireless communication systems. The work done so far around LiFi signifies the strengths and weaknesses of LiFi when compared to RF-based communications, especially in spectrum, spatial reuse, security and energy efficiency.

5G networks can offer an extremely high capacity for novel streaming applications. One of the most promising approaches is to embed large numbers of cooperating small cells into the macro-cell coverage area. Alternatively, LiFi can be adopted as an alternative physical layer, offering higher data rates. This is an emerging technology for future high capacity communication links (it has been accepted to 5GPP) in the visible range of the electromagnetic spectrum (~370–780 nm), utilizing light-emitting diodes (LEDs) to simultaneously provide data transmission and room illumination. A major challenge in LiFi is the LED modulation bandwidths, which are limited to a few MHz. However, myriad gigabit speed transmission links have already been demonstrated. Non-line-of-sight (NLOS) optical wireless is resistant to obstacles and is capable of adapting its throughput according to the current channel state information. Concurrently, organic polymer LEDs (PLEDs) have become the focus of attention for solid-state lighting applications. This is due to advantages over regular white LEDs such as ultra-low costs, low heating temperature, mechanical flexibility and large photoactive areas.

Also read: 5G Infra Challenges That LiFi (Light Communication) Solves & Its Core Benefits


Power efficiency has become one of the most important issues for 5G networks.

As the number of communication devices increases and the demand for connections grows. Around 2% of all carbon-dioxide emissions worldwide are produced by communication technologies; this will increase significantly as the mobile data traffic demand continuously surges. Moreover, ~57% of overall wireless network energy consumption is dissipated in radio access nodes. Thus, ‘green’ and energy-efficient systems can reduce CO2 emissions and decrease operating costs. Indoor communication systems can offer a solution to all the above issues via technologies like LiFi that can offer many advantages such as high capacity data transmission, excellent mobility and energy-efficient management.

Benefits of LiFi

  • Latency: Light Communication offers sub millisecond latency for wireless communication which will enable automation and enhances the AR/VR experience.
  • Security: “Light cannot trespass through the physical environment, enabling secure data passage”. The inherent property of light is adding up an extra physical layer of security for data transmission.
  • Localization: LiFi & OCC can enable precise localization of users as each light source has its own unique address which means advanced geofencing can be added in a LiFi network. With OCC, applications like precise asset tracking and indoor navigation can be enabled.
  • Energy Efficiency: LiFi provides connectivity utilising the current lighting infra-structure with very low additional requirement of power for communication part. This means we are saving more energy on data transmission side.

Is light communication capable of overcoming the future technology problems?

light communications

In our last blog, we discussed that the available Radio Frequency (RF) spectrum is not enough to cater to the growing demand for wireless data, and therefore, light communications (LC) play a vital role in overcoming this burden effectively and efficiently. But, is light communication technology really capable of solving our wireless network issues? Let’s find out.

Radio Frequency Vs. Light Communication

The number of devices accessing mobile network is increasing rapidly which is directly proportional to the mobile data traffic. Unfortunately, the RF spectrum is suffering to a great extent due to the high demand resulting in poor performance and high interference. With RF communication, comes the following problems:

  • Interference with other communication & navigation systems
  • Disruptions due to the bandwidth limitations
  • High congestion leading to low speed or inefficiency
  • Security issues as RF waves can easily penetrate through walls
  • Health hazards as more RF waves can be dangerous

Light Communications, on the other hand, have high bandwidth and are immune to any interference from electromagnetic sources. The light spectrum is globally unlicensed and can be utilised to communicate freely with low power consumption and the cost-effective deployment of the connectivity infrastructure. LC provides wireless data connectivity in spaces where the use of RF is unwanted or not secure or not possible. Isn’t it impressive?

Want high-speed internet to transfer your data? All you need is light!

In ancient times, the light was used to convey messages using methods such as fire and smoke signals. The Roman used polished metallic plates for sunlight reflection to carry out long-distance signaling.

And then, inventions in the field of science and technology happened. We got to discover and study things closely which broadened our scope of research work.

Also read: 5G challenges that LiFi (Light Communication) solves & its core benefits


Talking about light, we ought to explain what’s Electromagnetic Spectrum. It is the range of frequencies of electromagnetic radiation from zero to infinity, starting from the shortest wavelengths and high frequencies to the longest wavelengths and lowest frequencies. It includes a wide range of light waves, but we can only see light within a certain range of wavelengths and frequency.

Visible light is near the center of the spectrum, with intermediate wavelengths and frequencies. The non-visible types of waves include radio waves, microwaves, infrared rays, ultraviolet rays, X-rays, etc.

Visible Light Communication = Illumination + Communication

Visible Light Communication (VLC) is a data communication variant which uses visible light between 400 and 800 THz. This means that any form of information can be sent using visible light. To be precise, VLC is a method of transmitting data using LEDs.

As the visible light spectrum is 1000 times larger than the radio frequency spectrum, VLC is regarded as a solution to RF bandwidth limitations.

The visible light source is capable of saving the extra power as it can be used for both illumination as well as communication. And this makes VLC a cheaper deal as compared to RF communication. Moreover, since light cannot trespass through physical environments (like walls), it’s a more secure way of communicating confidential data.

Use Cases of Light Communication

1. High-Speed Indoor Wireless Networks (LiFi)

LiFi  is defined as a technology that uses the visible and infrared light spectrum to provide bi-directional (transmit and receive) capability. The LiFi framework involves multiple LED light bulbs that form a wireless communication network, offering a similar user experience to other wireless communication technologies such as Wi-Fi using the light spectrum. It comes with inherent wireless communication properties like multiple user access from single LiFi AP as well as complete mobility for users.

LiFi provides a high-speed, secure, dense and reliable wireless network for enterprise and home environments and acts as an enabler for smart buildings, intelligent transport, smart cities, and in the areas that are sensitive to electromagnetic radiation (such as aircrafts).

2. Wireless Backhaul Infrastructure for 5G/Telecom Operators

Unlike previous generations of mobile networks, the fifth generation (5G) technology is expected to fundamentally transform the role that telecommunications technology plays in the society. It is also expected to enable further economic growth and pervasive digitalisation of a hyper-connected society, where people are not only connected to the network whenever needed, but also to many other devices virtually creating an inter-connected society (i.e. Internet of Everything).

5G will, therefore, enable new use cases such as smart cities, smart agriculture, logistics and public safety agencies but simultaneously the spectral efficiency of 5G technology shall be much lower than the 3G or 4G/LTE. This will require densification of telecom infrastructure in terms of deployment of Macro cells and Small cells on every 150–200 meters i.e. lamp posts, building rooftops, public infrastructure, in-building cells etc.

Light communication based wireless backhaul solution for indoor & outdoor networks will be a future-proof and reliable backhauling solution not only for LTE and 5G but also for last mile connectivity in enterprise & FTTx broadband solutions.

3. Indoor Localisation for Retail Establishments/Airports

Light communication technology opens the door for retailers to engage and influence consumers on the retail floor more effectively.

LC enables way finding just like a GPS. It provides indoor location-positioning functionality that helps, for instance, shoppers in a mall to look for particular items, by guiding them in the right direction. The staff can also deliver targeted information to the customers regarding coupons or any other offers as they pass through a product section. All this can happen because light can communicate with smartphones with a camera.

Devices (such as sensors), can be incorporated within the LEDs to capture the traffic or activities at a store or huge offices. Similar mechanism creates huge value in all large establishments specifically airports where passengers can navigate to the desired location with ease. It also opens up augmented revenue generation opportunities for retailers & an accurate consumer/passenger behavior analytics for better product merchandising.

4. Vehicle to Vehicle Communication

LC can be used for communication in vehicles, thanks to the vehicle lights. They can detect a collision or any crashes, lane change warnings, emergency brakes, etc. We are moving in the era of highly secure & self-driving vehicles. LC can establish a complete wireless network on roads wherein each of the cars will be acting as a node.

5. Connectivity in Hospitals

In electromagnetic sensitive areas like hospitals, LC can play a vital role in preventing the interference of radio waves with other machines.

6. Underwater Communication

LC can be used in underwater communication using Un-Tethered Remotely Operated Vehicle (UTROV) for observatory maintenance of the oceans and ships’ deployment.

Thus, light communication is what we need, but it still has a long way to go. Have any queries? Comment below and let us know your feedback.

All That You Need To Know About Light Communication

What is lifi?

What is Light Communication?

Wireless communications have evolved incessantly corresponding to the needs and interests of today’s generation, but the available radio frequency spectrum is not enough to cater to the growing demand for wireless data. The spectrum crunch puts constraints on the increasing demand for global connectivity and high capacity leading to a data communication gap. Continue reading to know more about what is light communication, what are its benefits ? etc..

Did you know facts

What is Spectrum Crunch?

Spectrum crunch refers to the potential lack of sufficient wireless frequency spectrum needed to support a growing number of consumer devices. It is a risk in telecommunications and wireless networking with profound implications for the immediate future.

What is Light Communication?

High demand for such kind of reliable communication networks with better speed has led to the birth of light communications which is unlocking the unparalleled data and bandwidth.

LC devices are promising to make use of untapped spectrum of light — both visible and invisible, for communication. Both the visible light spectrum and the infrared spectrum are globally unlicensed.

Anywhere solid-state lights (e.g. LED lights) are installed to provide illumination, there can also be high-speed wireless data communications.

Velmenni facts

Benefits of Light Communication

Talking about the benefits of implementing LC, following are some of the many advantages:

i) Unlicensed Free Spectrum

Both the visible light spectrum and the infrared spectrum are globally unlicensed which can be utilised to communicate freely with low power consumption and the cost-effective deployment of the connectivity infrastructure.

ii) Safe & Secure Communications

Since light does not pass through opaque materials, it can offer a secure communications channel avoiding the leakage of any confidential information.

iii) Works well in RF-restricted environments

LC provides wireless data connectivity in environments such as petrochemical plants, hospitals, manufacturing plants, nuclear power generating stations, underground mines, underwater etc, where the use of RF is not wanted, not secure or actually impossible. Isn’t it great?

There are multiple technologies and concepts that use light for communications. For instance, the Infrared (IR) communications between a remote control and a television can be considered as light communications with very low data rate.

Technologies using the light spectrum for wireless communications are known as Optical Wireless Communications (OWC), broadly classified into three different categories:

  1. Free-Space Optics (FSO)

FSO is a technology that, via light dissemination in free space, wirelessly transmits data. By ‘Free space’ I mean — air, outer space, vacuum, or a similar medium. A clear contradistinction of FSO would be the optical fibre cables which are tangible and solid in nature. To sum up FSO, it is a line-of-sight technology which uses the invisible light to provide optical bandwidth connections.

This technology would be apt for Indoor/Semi Outdoor settings, enterprise-level offices & industrial environments for short and long reach communication.

2. Optical Camera Communications (OCC)

OCC is made for smart devices and its primary function is directly related to the device’s camera. It uses the visible and near-infrared spectrum for one-directional communications at very low data rates in a broadcast manner. OCC could be used to provide accurate indoor positioning and limited amounts of information similar to how the Global Positioning System (GPS) is used to offer positioning in outdoor scenarios.

OCC could be combined with RF technologies to provide location-based services. These systems have already been tested and effectively deployed at retail chains, shopping centres and large office venues to offer operational improvements.

3. Light Fidelity (LiFi)

LiFi is the revolutionary technology which enables transmission of data through light. LiFi can be defined as a fully networked optical wireless technology that leverages the spectrum of light instead of radio waves to exchange data. With LiFi, the possibilities are endless and the opportunities tremendous. The applications of LiFi ranges from using it at home or an office environment to streaming high-quality content during flights.

Spectrum of light, being 1000 times wider than the Radio Frequency can achieve significantly faster speed than Wi-Fi. The fact that light cannot trespass through the physical environment makes LiFi a secure bearer of data.

LiFi provides a high-speed, secure, dense and reliable wireless network for enterprise and home environments and acts as an enabler for smart buildings, intelligent transport and smart cities.

Benefits of Lifi

The applications for Light Communication are limitless. Needless to say that the use of light is indispensable in worldwide wireless communication networks forming the backbone of the Internet. What do you think?

We hope the article could give you a quick tour of the world of light communication. We, at Velmenni, are reimagining the role lights plays in the universe. Know more about LiFi here.