1 1. ABSTRACT

Wireless technology is evolving on all fronts in personal, local and wide area networks in some surprising directions. Despite being over a century old, it continues to improve at an ever-increasing rate. Yet all the past, present and future improvements stem from one underlying process, better engineering leading to more precise use of space and time. A set of new technologies are just coming into early use i.e. 802.11ac promises a Gigabit per second from a single access point; LTE-A is cutting out a path out to full mobile broadband integrated with direct local device-to-device communications and smart spectrum reuse is easing the bandwidth crunch. Further out, the promise of terabit systems combines with innovative reuse of existing ideas to provide more services further afield than ever before. All techniques currently in use such as 802.11ac, LTE and 60GHz rely on combining multiple channels across frequencies and spatial paths; processing multiple channels at once is an ideal task for today's massively-parallel giga-transistor chip architectures. Here are the latest developments in Wi-Fi, mobile broadband, white space radio and more. Gi-Fi is developed on an integrated wireless transceiver chip, in which a small antenna is used and both transmitter- receiver integrated on a single chip, are fabricated using the complementary metal oxide semiconductor (CMOS) process whereas Li-Fi is typically implemented using white LED light bulbs. These devices are normally used for illumination by applying a constant current through the LED. However, by fast and subtle variations of the current, the optical output can be made to vary at extremely high speeds. Unseen by the human eye, this variation is used to carry high-speed data,” says Dr Povey, Product Manager of the University of Edinburgh's Li-Fi Program ‘D-Light Project’.

2 2. INTRODUCTION

Whether you’re using wireless internet in a coffee shop, stealing it from the guy next door, or competing for bandwidth at a conference, you’ve probably gotten frustrated at the slow speeds you face when more than one device is tapped into the network. As more and more people and their many devices access wireless internet, clogged airwaves are going to make it increasingly difficult to latch onto a reliable signal. But radio waves are just one part of the spectrum that can carry our data. What if we could use other waves to surf the internet or any other alternate?

The first wireless signals to see practical use were Morse code broadband blasts of spark generated noise, interfering with any other signal within range. The invention of tuning allowed multiple signals to share the spectrum; better antennas meant the same frequencies could be reused without mutual interference; amplitude and frequency modulation meant more information could be carried on each signal.

The biggest break for wireless, as for all electronics, was the triumph of the transistor over the valve. From the 50s onwards. Moore's Law gave, and continues to give, engineers the ability to do more and more work on signals with lower power requirements and less cost. Wireless is doing particularly well from that process. All current techniques such as 02.11ac, LTE and 60GHz rely on combining multiple channels across frequencies and spatial paths, processing multiple channels at once is an ideal task for today's massively parallel giga-transistor chip architectures. This also ties in well with SDR (Software-Defined Radio) which relies on very fast processors to replicate mathematically the sort of signal processing that dedicated electronic circuits used to do. This means that a single SDR can manage multiple standards just by changing its programming, leading to some predictions that one chip could do the three main classes of wireless i.e. PAN, LAN and WAN (Personal, Local and Wide-area Networking). As yet, however, this remains economically less preferable than having some separation of services.

The next generation of general-purpose wireless network builds on ideas that saw first deployment in its predecessor which introduced MIMO (Multiple In, Multiple Out) to the mass market. By running multiple transmitters and receivers on the same channel but to multiple antennas, MIMO makes use of the tiny timing differences in the paths between each transmitter/receiver combination of to create parallel channels.

The 802.11n standard specified up to four parallel spatial channels, with individual channels set to a maximum of 40MHz bandwidth; 802.11ac increases that to eight parallel channels of 80MHz minimum, 160MHz optional. It also uses slightly more efficient ways to code the data onto the transmission channel: however, these are so close to the theoretical maximum i.e. the Shannon Limit that future improvements will have to come from wider channels and more of them.

In place of MIMO, spatial channels are created with beamforming or AAS (Adaptive Antenna Steering). Individual antennas at 60GHz are very small barely a couple of millimetres long, so densely populated arrays can be easily built and configured to create dynamic, tight beams that track moving devices. Known as 802.11ad (Gi-Fi) 60GHz Wi-Fi is specified to provide 7Gbps, although only at ranges of up to 10 metres and not through walls or windows. There, the standard will fall back to 802.11ac or slower.

3 Currently, the highest frequencies in use experimentally are in the range of 240GHz,

where the Fraunhofer Institute and other German researchers on the Millilink project have squeezed 40Gbps across a distance of a kilometre. They expect to use multiple channel technologies to get that up to the terabit range, making the technology suitable to replace fibre-optic links and provide last-mile connections to homes and offices. However, unlike fibre optic links, it does go downhill very fast in heavy rain showers.

If we could use other waves to surf the internet i.e. “Data Through Illumination” taking the fibre out of fibre optics by sending data through an LED light bulb that varies in intensity faster than the human eye can follow. It’s the same idea behind infrared remote controls, but far more powerful.

4 3. Li-Fi Technology Radio waves are just one part of the spectrum that can carry our data. What if we could use other waves to surf the internet? One German physicist Dr. Harald Haas, has come up with a solution he calls “Data Through Illumination” i.e. taking the fibre out of fibre optics by sending data through an LED light bulb that varies in intensity faster than the human eye can follow. It’s the same idea behind infrared remote controls, but far more powerful. Haas says his invention, which he calls D-Light, can produce data rates faster than 10 megabits per second, which is speedier than your average broadband connection. He envisions a future where data for laptops, smartphones, and tablets is transmitted through the light in a room. And security would be a snap—if you can’t see the light, you can’t access the data. Li-Fi is a VLC, visible light communication, technology developed by a team of scientists including Dr Gordon Povey, Prof. Harald Haas and Dr Mostafa Afghani at the University of Edinburgh. The term Li-Fi was coined by Prof. Haas when he amazed people by streaming high-definition video from a standard LED lamp, at TED Global in July 2011. Li-Fi is now part of the Visible Light Communications (VLC) PAN IEEE 802.15.7 standard.

“Li-Fi is typically implemented using white LED light bulbs. These devices are normally used for illumination by applying a constant current through the LED. However, by fast and subtle variations of the current, the optical output can be made to vary at extremely high speeds. Unseen by the human eye, this variation is used to carry high-speed data,” says Dr Povey, Product Manager of the University of Edinburgh's Li-Fi Program ‘D-Light Project’.

In simple terms, Li-Fi can be thought of as a light-based Wi-Fi. That is, it uses light instead of radio waves to transmit information. And instead of Wi-Fi modems, Li-Fi would use transceiver-fitted LED lamps that can light a room as well as transmit and receive information. Since simple light bulbs are used, there can technically be any number of access points. This technology uses a part of the electromagnetic spectrum that is still not greatly utilized- The Visible Spectrum. Light is in fact very much part of our lives for millions and millions of years and does not have any major ill effect. Moreover, there is 10,000 times more space available in this spectrum and just counting on the bulbs in use, it also multiplies to 10,000 times more availability as an infrastructure, globally. It is possible to encode data in the light by varying the rate at which the LEDs flicker on and off to give different strings of 1s and 0s. The LED intensity is modulated so rapidly that human eyes cannot notice, so the output appears constant. More sophisticated techniques could dramatically increase VLC data rates. Teams at the University of Oxford and the University of Edinburgh are focusing on parallel data transmission using arrays of LEDs, where each LED transmits a different data stream. Other groups are using mixtures of red, green and blue LEDs to alter the light's frequency, with each frequency encoding a different data channel. Li-Fi, as it has been dubbed, has already achieved blisteringly high speeds in the lab. Researchers at the Heinrich Hertz Institute in Berlin, Germany, have reached data rates of over 500 megabytes per second using a standard white-light LED. Haas has set up a spin-off firm to sell a consumer VLC transmitter that is due for launch next year. It is capable of transmitting data at 100 MB/s - faster than most UK broadband connections.

5 3.1. Genesis of LI-FI Harald Haas, a professor at the University of Edinburgh who began his research in the field in 2004, gave a debut demonstration of what he called a Li-Fi prototype at the TEDGlobal conference in Edinburgh on 12th July 2011. He used a table lamp with an LED bulb to transmit a video of blooming flowers that was then projected onto a screen behind him. During the event he periodically blocked the light from lamp to prove that the lamp was indeed the source of incoming data. At TEDGlobal, Haas demonstrated a data rate of transmission of around 10Mbps -- comparable to a fairly good UK broadband connection. Two months later he achieved 123Mbps. 3.2. How Li-Fi Works? Li-Fi is typically implemented using white LED light bulbs at the downlink transmitter. These devices are normally used for illumination only by applying a constant current. However, by fast and subtle variations of the current, the optical output can be made to vary at extremely high speeds. This very property of optical current is used in Li-Fi setup. The operational procedure is very simple-, if the LED is on, you transmit a digital 1, if it’s off you transmit a 0. The LEDs can be switched on and off very quickly, which gives nice opportunities for transmitting data. Hence all that is required is some LEDs and a controller that code data into those LEDs. All one has to do is to vary the rate at which the LED’s flicker depending upon the data we want to encode. Further enhancements can be made in this method, like using an array of LEDs for parallel data transmission, or using mixtures of red, green and blue LEDs to alter the light’s frequency with each frequency encoding a different data channel. Such advancements promise a theoretical speed of 10 Gbps – meaning one can download a full high-definition film in just 30 seconds.

6 To further get a grasp of Li-Fi consider an IR remote. It sends a single data stream of bits at the rate of 10,000-20,000 bps. Now replace the IR LED with a Light Box containing a large LED array. This system, is capable of sending thousands of such streams at very fast rate.

Light is inherently safe and can be used in places where radio frequency communication is often deemed problematic, such as in aircraft cabins or hospitals. So visible light communication not only has the potential to solve the problem of lack of spectrum space, but can also enable novel application. The visible light spectrum is unused, it's not regulated, and can be used for communication at very high speeds.

3.3. Application of Li-Fi Technology 3.3.1. You Might Just Live Longer You Might Just Live Longer for a long time, medical technology has lagged behind the rest of the wireless world. Operating rooms do not allow Wi-Fi over radiation concerns, and there is also that whole lack of dedicated spectrum. While Wi-Fi is in place in many hospitals, interference from cell phones and computers can block signals from monitoring equipment. Li-Fi solves both problems: lights are not only allowed in operating rooms, but tend to be the most glaring fixtures in the room. And, as Haas mentions in his TED Talk Li-Fi has 10,000 times the spectrum of Wi-Fi, so maybe we can delegate red light to priority medical data. Code Red! 3.3.2. Airlines Airline Wi-Fi. Ugh. Nothing says captive audience like having to pay for the "service" of dialup speed Wi-Fi on the plane. And don’t get me started on the pricing. The best I’ve heard so far is that passengers will "soon" be offered a "high-speed like" connection on some airlines. United is planning on speeds as high as 9.8 Mbps per plane. Uh, I have twice that capacity in my living room. And at the same price as checking a bag, I expect it. Li-Fi could easily introduce that sort of speed to each seat's reading light. I’ll be the guy wowing next to you. It’s better than listening to you tell me about your wildly successful son, ma’am.

7 3.3.3. Smarter Power Plants Wi-Fi and many other radiation types are bad for sensitive areas. Like those surrounding power plants. But power plants need fast, inter-connected data systems to monitor things like demand, grid integrity and (in nuclear plants) core temperature. The savings from proper monitoring at a single power plant can add up to hundreds of thousands of dollars. Li-Fi could offer safe, abundant connectivity for all areas of these sensitive locations. Not only would this save money related to currently implemented solutions, but the draw on a power plant’s own reserves could be lessened if they haven’t yet converted to LED lighting. 3.3.4. Undersea Awesomeness Underwater ROVs, those favourite toys of treasure seekers and James Cameron, operate from large cables that supply their power and allow them to receive signals from their pilots above. ROVs work great, except when the tether isn’t long enough to explore an area, or when it gets stuck on something. If their wires were cut and replaced with light —say from a submerged, high-powered lamp — then they would be much freer to explore. They could also use their headlamps to communicate with each other, processing data autonomously and referring findings periodically back to the surface, all the while obtaining their next batch of orders. 3.3.5. It Could Keep You Informed and Save Lives Say there’s an earthquake in New York. Or a hurricane. Take your pick —it’s a wacky city. The average New Yorker may not know what the protocols are for those kinds of disasters. Until they pass under a street light, that is Remember, with Li-Fi, if there’s light, you’re online. Subway stations and tunnels, common dead zones for most emergency communications, pose no obstruction. Plus, in times less stressing cities could opt to provide cheap high speed Web access to every street corner.

3.4. How it is different? Li-Fi technology is based on LEDs for the transfer of data. The transfer of the data can be with the help of all kinds of light, no matter the part of the spectrum that they belong. That is, the light can belong to the invisible, ultraviolet or the visible part of the spectrum. Also, the speed of the internet is incredibly high and you can download movies, games, music etc in just a few minutes with the help of this technology. Also, the technology removes limitations that have been put on the user by the Wi-Fi. You no more need to be in a region that is Wi-Fi enabled to have access to the internet. You can simply stand under any form of light and surf the internet as the connection is made in case of any light presence. There cannot be anything better than this technology.

3.5. Uses in Various Areas It can be used in the places where it is difficult to lay the optical fibre like hospitals. In operation theatre Li-Fi can be used for modern medical instruments. In traffic signals Li-Fi can be used which will communicate with the LED lights of the cars and accident numbers can be decreased. Thousand and millions of street lamps can be transferred to Li-Fi lamps to transfer data. In aircraft Li-Fi can be used for data transmission. It can be used in petroleum or chemical plants where other transmission or frequencies could be hazardous.

8 3.6. Advantages of LI-FI Li-Fi can solve problems related to the insufficiency of radio frequency bandwidth because

this technology uses Visible light spectrum that has still not been greatly utilized. High data transmission rates of up to 10Gbps can be achieved. Since light cannot penetrate walls, it provides privacy and security that Wi-Fi cannot.

Li-Fi has low implementation and maintenance costs. It is safe for humans since light, unlike radio frequencies, cannot penetrate human body.

Hence, concerns of cell mutation are mitigated. 3.7. Disadvantage of LI-FI

Light can't pass through objects. A major challenge facing Li-Fi is how the receiving device will transmit back to

transmitter. High installation cost of the VLC systems. Interferences from external light sources like sun, light, normal bulbs, opaque materials.

9 4. Gi-Fi(Gigabit Fidelity) For many years, cables ruled the world. Optical fibers played a dominant role because of its higher bit rates and faster transmission. But the installation of cables caused a greater difficulty and thus led to wireless access. The foremost of this is Bluetooth, which can cover 9-10metres. Wi-Fi followed it having coverage area of 91metres. No doubt, introduction of Wi-Fi (Wireless Fidelity) has brought a revolutionary solution to “last mile” problem. However, the standard's original limitations for data exchange rate and range, number of channels, high cost of the infrastructure have not yet made it possible for Wi-Fi to become a total threat to cellular networks on one hand, and hard-wire networks, on the other. But the man’s continuous quest for even better technology despite the substantial advantages of present technologies led to the introduction of new, more up-to-date standards for data exchange rate i.e., Gi-Fi. It will help to push wireless communications to faster drive. Gi-Fi or Gigabit Wireless is the world's first transceiver integrated on a single chip that operates at 60GHz on the CMOS process. It will allow wireless transfer of audio and video data up to 5 Gigabits per second, ten times the current maximum wireless transfer rate at one-tenth of the cost, usually within a range of 10 meters. It utilizes a 5mm square chip and a 1mm wide antenna burning less than 2 mw of power to transmit data wirelessly over short distances, much like Bluetooth. The development will enable the truly wireless office and home in the future. As the integrated transceiver is extremely small, it can be embedded into devices. The breakthrough will mean the networking of office and home equipment without wires will finally become a reality. Wi-Fi (IEEE-802.11b) and Wi-Max (IEEE-802.16e) have captured our attention. As there are no recent developments which Transfer data at faster rate, video information transfer is taking a lot of time. This leads to introduction of Gi-Fi technology. It offers some advantages over Wi-Fi, a similar wireless technology, which offers faster information rate (Gb/s), Less power consumption and low cost for short range transmissions. Gi-Fi is developed on an integrated wireless transceiver chip, in which a small antenna is used and both transmitter- receiver integrated on a single chip, are fabricated using the complementary metal oxide semiconductor (CMOS) process. In this part we present a low cost, low power and high broadband chip, which will be vital in enabling the digital economy of the future.

10 4.1. WHY Gi-Fi? The reason for pushing into Gi-Fi technology is because of slow rate high power consumption, low range of frequency operations of earlier technologies i.e., Bluetooth and Wi-Fi. See the comparisons and features of those two technologies. BLUETOOTH Vs WI-FI:

4.2. DISADVANTAGES OF BLUETOOTH AND Wi-Fi: From above table, we can conclude that the bit rate of Bluetooth is 800Kbps and Wi-Fi has 11Mbps. Both are having very high power consumption. As for GI-FI, it is less than 2 mw to transfer gigabytes of information. Bluetooth and Wi-Fi operate at a lower frequency of 2.4GHz whereas GI-FI operates at 60 GHz. 4.3. WHAT IS Gi-Fi? Gi-Fi or gigabit wireless is the world’s first transceiver integrated on a single chip that operates at 60GHz on the CMOS process. It will allow wireless transfer of audio and video data at up to 5 gigabits per second, ten times the current maximum wireless transfer rate, at one-tenth the cost. NICTA researchers have chosen to develop this technology in the 57-64GHz unlicensed frequency band as the millimetre -wave range of the spectrum makes possible high component on-chip integration as well as allowing for the integration of very small high gain arrays. The available 7GHz of spectrum results in very high data rates, up to 5 gigabits per second to users within an indoor environment, usually within a range of 10 metres. It satisfies the standards of IEEE 802.15.3C.

11

Gigabit wireless: The Gi-Fi integrated wireless transceiver chip developed at the National ICT Research Centre, Australia. — FUNDAMENTAL TECHNOLOGIES IN 802.15.3C:

This mm Wave WPAN will operate in the new and clear band including 57-64 GHz unlicensed band defined by FCC 47 CFR 15.255. The millimeter-wave WPAN will allow high coexistence (close physical spacing) with all other microwave systems in the 802.15 family of WPANs.

4.4. WORKING OF GI-FI: Here we will use time division duplex for both transmission and receiving. Data files are up converted from IF range to RF 60Ghz range by using 2 mixers. The output will fed be into to a power amplifier, which feeds millimetre wave antenna. The incoming RF signal is first down converted to an IF signal cantered at 5 GHz and then to normal data ranges. We use heterodyne construction for this process to avoid leakages due to direct conversion. Due to availability of 7GHz spectrum, the total data will be transferred within seconds. 4.4.1. WHY 60 GHz...? Here we will use millimetre wave antenna which will operate at 60GHz frequency which is unlicensed band. Because of this band, we are achieving high data rates. Energy propagation in the 60 GHz band has unique characteristics that makes possible many other benefits such as excellent immunity to co-channel interference, high security and frequency re-use.

12 Point-to-point wireless systems operating at 60 GHz have been used for many years for satellite-to-satellite communications. This is because of high oxygen absorption at 60 GHz (10-15 dB/Km). This absorption attenuates 60 GHz signals over distance, so that signals cannot travel far beyond their intended recipient. For this reason, 60GHz is an excellent choice for covert communications.

Oxygen Attenuation vs. Frequency 4.4.2. ULTRA WIDE BAND FREQUENCY USAGE: UWB, a technology with high bit rate, high security and faster data transmission. It is a zero carrier technique with low coverage area. So we have low power consumption. Ultra-Wideband (UWB) is a technology for transmitting information spread over a large bandwidth (>500 MHz) that should, be able to share spectrum with other users. Regulatory settings of FCC are intended to provide an efficient use of scarce radio bandwidth while enabling both high data rate personal-area network (PAN) wireless connectivity and longer-range, low data rate applications as well as radar and imaging systems. 4.5. FEATURES OF Gi-Fi: The Gi-Fi standard has been developed with many objectives in mind. These are summarized below:

High speed of data transfer: The main invention of Gi-Fi to provide higher bit rate. As the name itself indicates data transfer rate is in Giga bits per second. Speed of Gi-Fi is 5 Gbps., which is 10 times the present data transfer. Because of wider availability of continuous 7 GHz spectrum results in high data rates. Low Power Consumption: It consumes only 2 mw power for data transfer of gigabits of information. Whereas in present technologies it takes 10 mw power, which is very high.

13 High Security: Point-to-point wireless systems operating at 60 GHz have been used for many years by the intelligence community for high security communications and by the military, for satellite-to satellite communications. The combined effects of O2 absorption and narrow beam spread result in high security and low interference. Cost-effective: Gi-Fi is based on an open, international standard. Mass adoption of the standard, and the use of low-cost, mass-produced chipsets, will drive costs down dramatically, and the resultant integrated wireless transceiver chip which transfers data at high speed, low power at low price $10 only, which is very less as compare to present systems. As development goes on, the price will be decreased. Small Size: The chip, just 5 mm per side, has a tiny 1 mm antenna and uses the 60 GHz ‘millimetre-wave’ spectrum. Quick Deployment: Compared with the deployment of wired solutions, Gi-Fi requires little or no external plant construction. For example, excavation to support the trenching of cables is not required. Operators that have obtained licenses to use one of the licensed bands, or that plan to use one of the unlicensed bands; do not need to submit further applications to the Government. Once the antenna and equipment are installed and powered, Gi-Fi is ready for service. In most cases, deployment of Gi-Fi can be completed in a matter of minutes, compared with hours for other solutions. High Performance: One particular 60 GHz radio link is quickly reduced to a level that will not interfere with other 60 GHz links operating in the same geographic vicinity. Because of low interference it probably gives high performance. Other features: High level of frequency re-use enabled – communication, needs of multiple customers, within a small geographic region can be satisfied. It is also highly portable-we can construct where ever we want. It deploys line of sight operation having only shorter coverage area. It has more flexible architecture.

4.6. APPLICATIONS: There are many usage Scenarios that can be addressed by Gi-Fi. The following are some mobility usage applications of Gi-Fi.

14 4.6.1. In wireless pan networks:

4.6.2. Inter-vehicle communication system:

4.6.3. Broadcasting video signal transmission system in sports stadium:

Ad-hoc information distribution with Point-to-Point network extension:

15

Easy and immediate construction of temporal broadband network such as in exhibition-site for…Advertisement information distribution or Contents downloading service 4.6.4. mm-Wave video-signals transmission system:

4.6.5. Media access control (MAC) and imaging and others:

4.6.6. Video information transfer: By using present technologies video swapping takes hours of time, whereas by this we can transfer at a speed of Gbps.

16

Data transfer rate is same for transfer of information from a PC to a cell or a cell to PC. 4.6.7. Data Distribution at Apartments/condominiums:

Fig : mm-WAVE PAN for on demand transmission or/ re broadcasting of video information to Ad-hoc terminals. 4.7. IN FUTURE As the range is limited to shorter distances only, we can expect the broad band with more speed and low power consumption. 4.8. TECHNOLOGY CONSIDERATIONS: The Gi-Fi integrated transceiver chip may be launched by ending of this year by NICTA. Due to less cost of chip, so many companies are forward to launch with lower cost. The potential of mw-WPAN for ultra-fast data exchange has prompted companies like Intel, LG, Matsushita (Panasonic), NEC, Samsung, Si BEAM, Sony and Toshiba to form Wireless HD, an industry-led effort to define a specification for the next generation consumer electronics products.

17 5. SMALL CELLS The classic model of cellular wireless, with a relatively small number of high-capacity masts, doesn't scale up well to high densities of users consuming large amounts of bandwidth. The expected solution is the generic term for transmitters coping with from five to around 250 users. The smallest variant, the, is currently deployed to fill in coverage for families within a domestic household, with picocells intended for offices and mini- or metro-cells extending to campuses. Backhaul — the connection from the cell to the rest of the telephone system — typically piggybacks on the building's existing internet connectivity. The major issues with deploying enough small cells to provide extra bandwidth are in many cases as much political and commercial as technical. Frequency allocation and non-interference with other cells in the area can be taken care of through sensing of band occupancy, central database co-ordination and direct negotiations between cells in a Self-Organising Network (SON) architecture. However, the question of who pays for the backhaul bandwidth becomes very involved once a small cell is opened up to general public use, as opposed to whitelists of registered handsets. Detecting, characterising and alleviating interference when things go wrong also has high potential to employ more lawyers than engineers — a trait wireless has exhibited throughout its existence.

18 6. WHITE SPACE White space is the most recent innovation in wireless WAN, although it too shows convergent evolution with other, more conventional systems. Overlaying (literally) all existing frequencies, white space uses intelligent networks to sense, analyse, configure and use channels that may be allocated to other services but which aren't actually in use. This has the potential for high efficiencies, long ranges and high bandwidth (although not all three at once), which has led to a lot of hype and hopeful posturing. The most likely applications may be rural broadband (although more traditional options are usually available there) and low-speed, high-density Internet-of-Things applications where meters and sensors report back a few tens or hundreds of bits per second on average to a central controller, and accept similarly slow commands back. White space does lend itself quite well to developing nations, where there are far fewer existing occupants of allocated bands and, often, significant rural populations in regions of little existing infrastructure. One of the more arresting concepts is Google's 'Skynet', which proposes to use tethered blimps and white space systems to illuminate large areas with affordable wireless broadband. Flying broadcast transmitters are not a new idea, dating back to at least the 1920s; what's new is the combination of low power, high bandwidth and physical lightness in long-duration unmanned lighter-than-air platforms.

19 7. P-Cell p-Cell is a revolutionary new approach to wireless, dramatically increasing the spectral efficiency of LTE and Wi-Fi systems, while remaining compatible with standard LTE and Wi-Fi devices. p-Cell technology is a radical new approach to wireless that increases the capacity of LTE and Wi-Fi networks by over an order of magnitude, while dramatically improving Quality of Service (Q o S) and maintaining off-the-shelf compatibility with unmodified LTE and Wi-Fi devices, such as iPhone, i-Pad and Android devices. p-Cell meets proposed 5G performance targets today, while remaining compatible with 4G devices. p-Cell technology accomplishes this through an entirely new approach to wireless: rather than avoiding interference like cellular or Wi-Fi systems, p-Cell embraces interference, utilizing interfering transmissions to synthesize a tiny personal cell, a “p-Cell”, around each individual user device, enabling every user to utilize the full capacity of the spectrum at once. Instead of many users sharing the limited capacity of one cell, resulting in steadily declining data rates as new subscribers join the network, with p-Cell technology, each user gets a personal cell. So, no matter how many users are sharing the same spectrum, each user is able to experience the full capacity of the spectrum concurrently with other users. p-Cell has a wide range of advantages over conventional wireless technologies: 7.1. Leapfrog in spectral efficiency: LTE networks today achieve a spectral efficiency

(SE)1 of 1.7 bps/Hz2. Practical p-Cell systems today achieve average spectral efficiency of 59 bps/Hz, a 35 times leapfrog with unmodified standard LTE devices, such as iPhone 6/6 Plus, i-Pad Air 2 and Android devices, as well as Wi-Fi devices. p-Cell’s spectral efficiency scales indefinitely, while remaining compatible with legacy devices.

7.2. Consistent, reliable data rate: Cellular or Wi-Fi data rate drops off rapidly from cell

centre (e.g. 100 Mbps) to cell edge (e.g. 1 Mbps), resulting in highly variable and unreliable service quality. With p-Cell the data rate remains uniformly near peak throughout the coverage area, including vertically in tall buildings, enabling Q o S service offerings, such as 4K UHD video.

7.3. Low deployment, operations cost: Cellular radios must be carefully placed in specific locations within a “cell plan” with antennas carefully aimed to avoid interference and dead zones. p-Cell deployment is fast with minimal real-estate and front haul costs because inexpensive p-Wave radio heads can be placed anywhere in the coverage area, allowing carriers to choose low-cost real estate locations that have line-of-sight (or low-cost fiber) paths for front haul.

20 8. FURTHER OUT STILL Automated transport, from self-driving cars to warrior drones on the front line, will make even more demands on wireless infrastructure, and will require much greater reliability and guaranteed connectivity. Research is looking at reusing existing infrastructure in new ways: a mobile phone network can be used as one component in a radar system for example; or very dense peer-to-peer networks using short, extremely fast high-bandwidth packets can provide a secondary underlying connectivity matrix that's very robust and resistant to congestion or interference. It will take heroic levels of reliable global bandwidth for people to accept drone passenger aircraft, for example, but the components are being put in place. Wireless hasn't finished changing the world.

21 9. CONCLUSION: Within five years, we expect Gi-Fi to be the dominant technology for wireless networking. By the time its fully mobile, as well as providing low-cost high broadband access with very high speed, Large files can be swapped within seconds which will develop wireless home and office of future. If the success of Wi-Fi and the imminent wide usage of WiMAX is any indication, Gi-Fi potentially can bring wireless broadband to the enterprise in a new way. The possibilities are numerous and can be explored further. If his technology can be put into practical use, every bulb can be used something like a Wi-Fi hotspot to transmit wireless data and we will proceed toward the cleaner, greener, safer and brighter future. The concept of Li-Fi is currently attracting a great deal of interest, not least because it may offer a genuine and very efficient alternative to radio-based wireless. As a growing number of people and their many devices access wireless internet, the airwaves are becoming increasingly clogged, making it more and more difficult to get a reliable, high-speed signal. This may solve issues such as the shortage of radio-frequency bandwidth and also allow internet where traditional radio based wireless isn’t allowed such as aircraft or hospitals. One of the shortcomings however is that it only work in direct line of sight.

22 10. REFERENCES:

1. NICTA Documents (www.nicta.com.au) 2. IEEE Chapters. 3. www.howstuffworks.com 4. LTE-Advanced (http://en.wikipedia.org/wiki/LTE_Advanced) 5. http://en.wikipedia.org/wiki/IEEE_802.11n-2009) 6. (http://en.wikipedia.org/wiki/MIMO) 7. (http://en.wikipedia.org/wiki/Shannon_Limit) 8. (http://en.wikipedia.org/wiki/Beamforming) 9. http://en.wikipedia.org/wiki/802.11ad) 10. (http://wirelessgigabitalliance.org/) 11. (http://wirelessgigabitalliance.org/news/wi-fi-alliance%C2%AE-and-wireless-gigabit-alliance-tounify/))

12. small cells (http://en.wikipedia.org/wiki/Small_cell) 13. femtocell (/article/vodafone-sure-signal-inside-a-femtocell 14. Self-Organising Network (http://en.wikipedia.org/wiki/Self-organizing_network) 15. (http://en.wikipedia.org/wiki/White_spaces_(radio)) 16. (http://online.wsj.com/article/SB10001424127887323975004578503350402434918.html

17. (http://eandt.theiet.org/news/2013/may/af-radar.cfm) 18. GPP, “Feasibility study for further advancements for E-UTRA (LTE-Advanced)”, TR 36.912, v 12.0.0, (36912-c00.doc) Sep. 2014.

19. Rysavy Research, “Beyond LTE: Enabling the Mobile Broadband Explosion”, Aug. 2014.

20. IMT-2020 (5G) Promotion Group, “IMT Vision towards 2020 and Beyond”, Feb. 2014.

21. 4. Other visions for 5G performance include: [NSN 2014], Nokia Siemens Networks “5G use case and requirements”, Apr. 2014.

22. In 40 MHz of spectrum with devices capable of carrier aggregation of two 20 MHz bands. [Rysavy 2014].

23. T. Rappaport, et al. “Millimeter wave mobile communications for 5G cellular: it will work!”, IEEE access, vol.1, pp.335-349, May 2013.

24. E. Larsson, O. Edfors, and T.L. Marzetta, “Massive MIMO for next generation wireless systems”, IEEE Comm. Magazine, pp.186-195, Feb. 2014.

25. http://www.gsmamobileeconomy.com/GSMA_ME_Report_2014_R_NewCover.pdf). 26. Video streaming today accounts for more than 50% of mobile data traffic [Cisco VNI 2014].