GJTE-Vol(1)-Issue(5) Dec 2014 ISSN: 2393-9923

Global Journal of Trends in EngineeringStratellitesA.Roja1, S.Sai Udaya Keerthy2,K. Krishna Keerthi31,2,3 Dept. of ECE, G. Pullaiah College of Engineering and Technology, Nandikotkur Road, Kurnool, Andhra Pradesh, IndiaE-Mail: arani.roja@gmail.com

ABSTRACT: Wireless communication is simply data communication without the use of landlines.This may involve cellular telephone,two-way radio ,fixed wireless(broadband wireless),laser(free space optics) orsatellite communication Mobile wireless technology are going to act as glue towards bringing together the wired and wireless to share and distribute information seamlessly across each others areas of reference .The paper firstly introduces the wireless communication and then switches to fourth generation in wireless communication .The paper then discusses about high altitude airships, the stratellites which are actually unmanned Kelvar balloons filled with helium which are used instead of towers for wireless communications, each of which replace hundreds of towers and reduces the cost of wireless communications. They also overcome the disadvantage of simple towers which could not provide proper coverage in hilly areas.

I. INTRODUCTIONSince from beginning of wireless communications there have been a number of developments in each generation Considering the future generation of wireless communication 4G.

4thGeneration:To achieve the goals of true broadband cellular service, the systems have to make the leap to a fourth-generation(4G )network.4G is intended to provide high speed, high capacity, low capacity per bit, IP based services. The goal is to have data rates up to 20 Mbps. Most probably the 4G would be a network which is a combination of different technologies (current cellular networks, 3G cellular networks,wireless LAN, etc.)4G cellular systems should not only be high-speed but also high capacity with low bit cost, high capacity with reasonable frequency bandwidth, the cell radius of 4G-cellular systems shall be decreased from that of present cellular system..4G Mobile Communication SystemsSome of the systems for future mobile communications are:1. Broad-Band Wireless Systems2. Intelligent Transport Systems3. High Altitude Stratospheric Platform Station Systems.High Altitude Stratospheric Platform Station Systems (HAPS) HAPShas the potential to become the third communications infrastructure after terrestrial and satellite communications. The platforms keep their positions at about 20 km high in the stratosphere. By optical intercommunication links, they make a mesh-like network in the sky. A broadband access link is the link between the platform station and the user station. The typical bit rate of the access link is 25 Mb/s for most fixed and portable terminals, while a several hundred megabits per second link is available for limited fixed terminals with antennas larger than the typical ones.

WHAT IS A STRATELLITE????A stratellite is similar to a satellite,but is stationed in the stratosphere rather than on the orbit. Stratellite is High-Altitude Telecommunication air ship for cellular, 3G and 4G mobile, MMDS, paging and fixed wireless telephony.

WHY ARE WE OPTING STRATELLITES????Though we have satellites we are opting stratellites mainly because of two drawbacks:1. Signal Latency: This signal latency can cause problems in establishing broadband links .Most telecommunication satellites are in geostationary orbits to remain above a certain point on the earths surface. That orbit ,however ,is 22,240 miles above the earth(i.e., in the area called CLARKE) ,which means that a signal going up to the satellite(Uplink) and back to the earth(Downlink) travels nearly 45,000 miles, which equates to about a quarter of a second delay. Even users of satellite voice links notice the delay.

2. The satellites are in space, requiring expensive space launches ,an additional level of regulation by national space authorities and an orbital allotment by the International Telecommunications Union(ITU).Also they include noise and interference due to large distance between transmitter and receiver units.

II. STRATOSPHERE+SATELLITE

Stratellite is a High Altitude Airship,25 times larger than good year blimp which is positioned approximately 13 miles above the earth, which provides the benefits of a satellite like remote sensing, navigation and communication.The altitude places these airships above both commercial airspace traffic and weather effects but significantly lower than standard low earth orbits.From this height stratellites can service a 300,000-square-mile-area.The North American Aerospace Defense Command (NORAD) projects that eleven such airships could provide radar coverage of the entire maritime and southern borders of the United States.

Each satellite will have clear line of site communication capability to an entire major-metropolitan area as well as being able to provide coverage across major rural areas. The stratellite is designed to carry certain payloads into the stratosphere determined by the requirements of the customer .A single unit could send broadband, mobile phones and digital television and radio signals to a large area. The unmanned stratellite would be powered by solar cells and propelled by electric motors. CONSTRUCTION OF STRATELLITEThe initial stratellite was 188ft long, 60ft wide and 42ft high. It is provided with a new steering method which uses a hybrid electric system that drives large, slow-turning propellersthis gives the airship helicopter-like agility by being able to move both up and down, side to side.The outside layer, orenvelope, is made out of a high-tech material called spectra. Spectra are a fabric used in bulletproof vests and part of space shuttles. Spectra contain fibre 10 times as strong as steel of the same weight and has the unique features of being easy to cut but virtually impossible to tear.The inide layer made from a thin but strong polyester film called Mylar, is fitted inside the envelope and filled with a mixture of helium and air. They use thin-film photovoltaic cells sprayed on their surfaces to generate electricity, which drives propellers to keep the stratellite positioned over one spot on the Earths surface.Stratellite consists of: Propeller Solar cells Regenerative fuel cells Helium gas bag Transponder Hybrid electric motors

STUCTURE OF STRATELLITELike great airships of 1930s the stratellites are whales of the sky.The prototypeSanswire One is 188ft long and shaped like double wired dirigible. It is a dirigible. The skeleton is a thin frame of high strength aluminum.The skin is a light colored Du Pont Tedlar, a polyvinyl fluoride film that clings tightly to protect the innards of the craft. Inside are helium lift cells and the communications gears that make the stratellite a wireless repeater for broadband internet, including VoIP (Voice over internet protocol, voice over internet packet, video over internet protocol), and perhaps cellular telephone and video transmission.WORKINGInside layer is filled with helium gas;it is an inert gas and is therefore not flammable.With this design,the helium expands as the airship raises forcing air out by propellers and lifting the airship. It uses solar cells sprayed on their surface to generate electricity.The generated electricity drives propellers that work withGPS technology to keep the stratellite stationary.Since helium is inert and non -flammable, with this design the helium expands as the air ship raises forcing air out and lifting the air ship. The cycle continues, allowing the airship to gain more and more altitude until the helium has expanded to fill the envelope completely. Because the pressure is slow inside the envelop a puncture would only result in a very slow leak, taking a long time to totally deflate, projected to carry pay loads as large as 4000 pounds, and later models are expected to carry over 20,000 pounds of radars and other remote imaging equipment, navigational aids, and telecommunication relays.Stratellites areplanned to remain on station for a year at a time and will cost a fifth as much as a comparable satellite.

APPLICATIONS:Stratellites will provide national broadband wireless network that will provide voice, video and broadband internet access to all parts of the country. By linking several stratellites together they can provide a wireless broadband network that will cover thousands of miles. With stratellite network, subscribers will be able to sit in their homes and be connected on their laptops to the internet at high speed. If the subscribers need to go to the office, across towns, or even to another city, they can close their laptop and take off, reopening the laptop at their new destination and still be connected to the internet In environmental disasters telecommunication breaks down within seconds, Re-installation of the infrastructure takes weeks or months. The stratellite can be used a floating mobile telecommunication station for all telecommunication purposes and transmission of temporary data communication, telecommunication and TV programs as well as long-term machines over metropolitan cities. This would allow subscribers the ease of not having to find local access numbers, tie up phone lines, deal with modem hassles, and more importantly, slow speed. The stratellite will allow subscribers to easily communicate in both directions using readily available wireless devices. In addition to voice and data, proposed telecommunication uses include cellular, 3G/4G mobile, MMDS,paging, fixed wireless telephony, HDTV, real-time surveillance and OTHERS.III. STRATELLITES AND TELECOMMUNCATION:Stratellites offer a window of telecommunications opportunity .Effectively, astratellite positioned over a major metropolitan area could act as a cell tower thirteen miles high. A stratellite, equipped with the appropriate transponders, could manage the wireless needs of that entire metropolitan area. Transponder access could be leased to broadband users such as Internet Service Providers (ISPs), cellphonecompanies, televisionnetworks, radio stations, various levels of government, and to corporations with large broadband requirements. These consumers could then resell access to end users, for residential Internet access, for example.None of this type of business or wireless use is innovative, so existing regulatory schemes and business models cover Stratellite communications. In fact, stratellite employed in this manner would make use of existing spectrum allocations, at least initially, and not require expensive bandwidth acquisition. Additionally, the marketing of such links would be virtually identical to current marketing. By increasing the utility and availability for the type of link that has, until now been restricted to satellites, firms can bring broadband links to new areas, provide for increased usage, and service larger markets without any fundamental change in operations.Application case: Googles Project Loon.

ADVANTAGES: Decreases signal latency. Less expensive to launch. Service an area of 300,000square-miles. Two-way high speed data communication. High speed broad-band access even in remote areas. For a country two stratellite are enough instead of thousands of towers. Planned to remain on station for a year at a time and will cost a fifth as much as a comparable satellites. Prototype airships are projected to carry payloads as large as 4,000 pounds, and later models are expected to carry over 20,000 pounds of radars and other remote imaging equipment, navigational aids, and telecommunication relays. In remote areas, over the oceans, in metropolises and in areas stricken by disasters, stratellites will immediately provide broadband access and broadband capacity.

MARKETABILITY AND COSTS:Some telecommunications providers, such as Sanswire Technologies, have recognized this marketing opportunity and already have formed joint ventures with the space industry and balloon-makers. However, in addition to marketing, Stratellites will require ground control and maintenance, and used Stratellites will require refurbishment before redeployment, tasks which the manufacturers and marketers may well lack the capacity or desire to perform.

Using wireless equipment, a company would have to install over 14,000 cellular towers to cover the same area as Sanswires proposed Stratellite based national wireless network. That means that there will be over 14,000 more ugly towers to hide. In addition, this technology will make the need for expensive cabling obsolete. One of the many advantages our High Altitude Airships have over satellite technology is that the payload can easily be recovered, upgraded, and re-launched in a matter of hours. Thus, each airship can be retrieved and re-used. Overall, the idea of a Stratellite wireless network seem to be marketable in the sense that they would be more cost effective than satellites and cellular towers, and with the proper testing they potentially have the ability to turn the whole country in one giant hot spot.STRATELLITE CHALLENGES AND BUSINESS OPPORTUNITES:Though the opportunities for increasing broadband links and for profit or enormous, stratellites are still in their infancy.They present several problems that have yet to be fully addressed. The public may be concerned about such large, unmanned payloads stationed above metropolitan areas and recent developments in sub-orbital flight could eventually lead to traffic problems in stratosphere. More importantly, critics question whether technology really exists that can keep stratellites on station for such long periods of time. Once these concerns are overcome and working of stratellites is available, the potential exists for vastly expanding broadband links.Some telecommunication providers, such as Sanswire Technologies, have recognized this marketing opportunity and already have formed joint ventures with space industry and balloon-makers. However,in addition to marketing, stratellites will require ground control and maintenance, and used stratellites will require refurbishment before redeployment, tasks which the manufacturers and marketers may welllack the capacity or desire to perform.

IV.FUTURE SCOPE:Once the defects of stratellites have been overcome and become more reliable, they play a vital role in future generation wireless communication. This is a promising technology that could combine the best of satellites and wired Internet-fast with low latency and hugely widespread, at least in theory.

V.CONCLUSIONStratellite provide the required facilities of the wireless communication more efficiently than the ordinary towers. The stratellite will allow the subscribers to easily communicate in both directions using readily available wireless technology. They minimize the cost of communication. Stratellite present a mobile, low-cost, high-capacity alternative to satellite relays and cell towers. Once the defects of stratellites have been overcome and become more reliable, they play a vital role in the future generation wireless communication.

REFERENCES[1] www.google.co.in[2] www.yahoosearch.com[3] Howstuffworks.com[4] 21stCentury Airships ,Inc., High Altitude Platy http://www.21stcenturyairships.com/[5] GeostationaryOrbits, in Wikipedia, athttp://en.wikipedia.org/wiki/Geostationary_orbit (last accessed Sept.28,2004).[6] TWUF,Broadband Takes to the Skiesrt Tech dirt, Get Your Wireless Broadband By Stratellites

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