--          CHAPTER 1     INTRODUCTION TO THE TOPIC                 1
INTRODUCTION OF THE TOPICThe use of high bandwidth applications is increasing rapidly, with increasedconsumer demand for s...
Disaster control and management The Gujarat earthquake is a case in point ofwhere broadband wireless networks could have b...
CHAPTER 2INTRODUCTION OF THE ORGNIZATION               4
BROADBAND OVERVIEW      Broadband is often called high-speed Internet, because it usually has a highrate of data transmiss...
as MPEG-2 video requires about 6 Mbit/s for good results. Adequate video for somepurposes becomes possible at lower data r...
Multilinking Modems       It is possible to roughly double dial-up capability with multilinking technology.What is require...
ISDN lines with 30 DS0 channels and total speed of 2,048 kbit/s. Because ISDN is atelephone-based product, a lot of the te...
equipment costs, but each rural customer may require expensive equipment to getconnected. A similar problem existed a cent...
wave 233 milliseconds to travel from ground to the satellite and back to the ground, atotal of 70,000 km (44,000 miles) to...
Power-line InternetThis is a new service still in its infancy that may eventually permit broadband Internetdata to travel ...
Traditional 802.11b was licensed for omni directional service spanning only 100-150meters (300-500 ft). By focusing the si...
limits. For comparison, note that a typical standard-definition movie is 700mb-1.2GB,while a high-definition movie is 6GB-...
Future broadband implementations      White Spaces Coalition a group of technology companies aiming to deliverbroadband in...
CHAPTER 3LITRATURE REVIEW       15
INDIAN BROADBAND MARKETThe telecom world may still be marveling at Indias mobile telephony growth, whichat 100 million con...
proliferate over wireless using specifically the WiMax technology, and formulatespolicies so that prices of end user equip...
The report says that VSNL has also announced Phase 1 pre-WiMax deploymentalthough there is clearly insufficient spectrum.G...
to help out in the successful implementation of broadband in Rural India withspecialattention to the areas ofa) Healtcareb...
especially from unrelated providers, they are unlikely to be affected by the sameservice outage.       Providing nomadic c...
Some cellular companies are evaluating WiMAX as a means of increasing bandwidthfor a variety of data-intensive application...
solitary hub are likely to be small in comparison to developing a wired solution. Areasof low population density and flat ...
The original version of the standard on which WiMAX is based (IEEE 802.16)specified a physical layer operating in the 10 t...
ArchitectureThe WiMAX Forum has defined an architecture that defines how a WiMAX networkconnects with other networks, and ...
NSP: a Network Service Providerplus a number of interconnections (or reference points) between these, labeled R1 toR5 and ...
each flow. Wi-Fi has introduced a QoS mechanism similar to fixed Ethernet, wherepackets can receive different priorities b...
Analog TV bands (700 MHz) may become available for WiMAX use, butawait the complete rollout of digital TV, and there will ...
Intel is a leader in promoting WiMAX, and has developed its own chipset. However, itis notable that most of the major semi...
Improving capacity and coverage by introducing Adaptive Antenna Systems(AAS) and Multiple Input Multiple Output (MIMO) tec...
3G cellular phone systems usually benefit from already having entrenchedinfrastructure, being upgraded from earlier system...
As a short-range mobile Internet solution, such as in cafes and at transportationhubs like airports, the popular Wi-Fi 802...
Mobile Inter                                 Mobile rangeWiBro         WiBro                   OFDMA         50      50   ...
UPA                                        OFDMA/MIMO                     Still         in                  UMTS/4G    LTE...
smart, granular network topologies. 3GPP LTE and WiMAX-m are concentratingmuch effort on MIMO-AAS, mobile multi-hop relay ...
A Wi-Fi enabled device such as a PC, game console, cell phone, MP3 player orPDA can connect to the Internet when within ra...
As of 2007 Wi-Fi technology had spread widely within business and industrialsites. In business environments, just like oth...
weaknesses. New protocols for Quality of Service (WMM) make Wi-Fi more suitablefor latency-sensitive applications (such as...
this problem and is now available on most products. Wi-Fi Access Points typicallydefault to an "open" (encryption-free) mo...
Wi-Fi 5 GHz product, (802.11a, or the newer 802.11n if it has 5 GHz support) as the5 GHz band is relatively unused and the...
handsets and thus no paying customers. These were both on the W-CDMAtechnology.The first commercial United States 3G netwo...
Europe the leading country is Italy with a third of its subscribers migrated to 3G.Other leading countries by 3G migration...
and cost of the handset. As a result, early European W-CDMA phones weresignificantly larger and heavier than comparable Ja...
fulfills    the   IMT-2000   standard.   This    system   is   called   Universal   MobileTelecommunications System (UMTS)...
In Japan, two 3G standards are used: W-CDMA used by NTT DoCoMo (FOMA,compatible with UMTS) and SoftBank Mobile (UMTS), and...
Mobile switching centre (MSC) (vendor dependent)         Authentication centre (AUC)         Serving GPRS Support Node (SG...
Lack of buy-in by 2G mobile users for the new 3G wireless services         Lack of coverage, because it is still a new ser...
to integrate services and content to tie them together. Within businesses andinstitutions, IPTV eliminates the need to run...
human hearing, and recording the remaining information in an efficient manner. Thisis relatively similar to the principles...
transient, 192 samples are taken instead of 576. This is done to limit the temporalspread of quantization noise accompanyi...
compressed, artifacts such as ringing or pre-echo are usually heard. A sample ofapplause compressed with a relatively low ...
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
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Future of  broadband in india
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Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
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Future of  broadband in india
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Future of  broadband in india
Future of  broadband in india
Future of  broadband in india
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THIS IS A BRIEF DISCUSSION AND DETAIL OF BROADBAND IN OUR INDIA NEAR FUTURE...

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Future of broadband in india

  1. 1. -- CHAPTER 1 INTRODUCTION TO THE TOPIC 1
  2. 2. INTRODUCTION OF THE TOPICThe use of high bandwidth applications is increasing rapidly, with increasedconsumer demand for streaming content such as video on demand, as well as peer-to-peer file sharing,3G , MP3,IPTV all these require bandwidth.For ISPs who are bandwidth limited, the "all you can eat" model may becomeunsustainable as demand for bandwidth increases. Fixed costs represent 80-90% ofthe cost of providing broadband service, and although most ISPs keep their costsecret, the total cost (January 2008) is estimated to be about $0.10 per gigabyte.Currently about 5% of users consume about 50% of the total bandwidth.Some ISPs have begun experimenting with usage based pricing, notably a TimeWarner test in Beaumont, Texas. Bell Canada has imposed bandwidth caps oncustomers, with pricing ranging from $1 to $7.50 per gigabyte for usage over certainlimits. For comparison, note that a typical standard-definition movie is 700mb-1.2GB,while a high-definition movie is 6GB-12GB. This could conceivably result in a chargeof $90 to view a movie Increasingly, all forms of electronic information telephony, data traffic, andTV and radio are being converted into digital format, making it possible for a singlenetwork to handle all of them. Also, there Is a continuing demand to transport moreinformation, more quickly. The result is a need for communication links with hugebandwidth. Broadband is a possible answer.Broad connectivity optionsHigh-speed Internet access and Remote LAN access are just the beginning ofbroadband. Other applications that will be made possible include videoconferencing,desk-to-desk video, interactive CAD, and collaborative working. 3G wirelessnetworks (based on broadband) will lead to applications such as mobile multimedia,mobile videoconferencing, etc.Service providers will be able to provide demand-based differentiated services suchas Internet access combined with voice and video on demand to customers, and inturn benefit from improved revenues. Demand-based services will allow users tochoose the bandwidth they require.Here Is how broadband wireless networks will provide solutions. 2
  3. 3. Disaster control and management The Gujarat earthquake is a case in point ofwhere broadband wireless networks could have been deployed. Ad hoc wirelessbroadband networks would have come in handy in Gujarat when all means ofcommunication failed, especially for sending multimedia information. This could beonline help from a surgeon to a medic who Is providing aid to disaster victims; orschedules, distribution plans, and remote monitoring of relief material.Military and defence Wireless broadband networks would enable military toexchange multimedia information while on the move. In many tactical scenarios, theeffective use of these networks may become the difference between victory anddefeat.Mobile videoconferencing For the busy business managers of the future and fortelecommuting workers operating from anywhere, wireless broadband datacommunication may become a great asset.Remote monitoring of industrial plants Engineers can monitor industrial plants rightfrom their mobile handset, rather than go to the plant or its monitoring station.As you can see, broadband access can lead to more useful applications for endusers and new revenue generation models for network operators providingbroadband services. 3
  4. 4. CHAPTER 2INTRODUCTION OF THE ORGNIZATION 4
  5. 5. BROADBAND OVERVIEW Broadband is often called high-speed Internet, because it usually has a highrate of data transmission. In general, any connection to the customer of 256 kbit/s(0.256 Mbit/s) or more is considered broadband Internet. The InternationalTelecommunication Union Standardization Sector (ITU-T) recommendation I.113 hasdefined broadband as a transmission capacity that is faster than primary rate ISDN,at 1.5 to 2 Mbit/s. The FCC definition of broadband is 200 kbit/s (0.2 Mbit/s) in onedirection, and advanced broadband is at least 200 kbit/s in both directions. TheOrganization for Economic Co-operation and Development (OECD) has definedbroadband as 256 kbit/s in at least one direction and this bit rate is the most commonbaseline that is marketed as "broadband" around the world. There is no specificbitrate defined by the industry, however, and "broadband" can mean lower-bitratetransmission methods. Some Internet Service Providers (ISPs) use this to theiradvantage in marketing lower-bitrates connections as broadband. In practice, the advertised bandwidth is not always reliably available to thecustomer; ISPs often allow a greater number of subscribers than their backboneconnection can handle, under the assumption that most users will not be using theirfull connection capacity very frequently. This aggregation strategy works more oftenthan not, so users can typically burst to their full bandwidth most of the time;however, peer-to-peer (P2P) file sharing systems, often requiring extended durationsof high bandwidth, stress these assumptions, and can cause major problems forISPs who have excessively overbooked their capacity. For more on this topic, seetraffic shaping. As take up for these introductory products increases, telcos arestarting to offer higher bit rate services. For existing connections, this most of thetime simply involves reconfiguring the existing equipment at each end of theconnection.As the bandwidth delivered to end users increases, the market expects that video ondemand services streamed over the Internet will become more popular, though atthe present time such services generally require specialized networks. The datarates on most broadband services still do not suffice to provide good quality video, 5
  6. 6. as MPEG-2 video requires about 6 Mbit/s for good results. Adequate video for somepurposes becomes possible at lower data rates, with rates of 768 kbit/s and 384 kbit/s used for some video conferencing applications, and rates as low as 100 kbit/s usedfor videophones using H.264/MPEG-4 AVC. The MPEG-4 format delivers high-quality video at 2 Mbit/s, at the high end of cable modem and ADSL performance. Increased bandwidth has already made an impact on newsgroups: postings togroups such as alt.binaries.* have grown from JPEG files to entire CD and DVDimages. According to NTL, the level of traffic on their network increased from a dailyinbound news feed of 150 gigabytes of data per day and 1 terabyte of data out eachday in 2001 to 500 gigabytes of data inbound and over 4 terabytes out each day in2002.Technology The standard broadband technologies in most areas are DSL and cablemodems. Newer technologies in use include VDSL and pushing optical fiberconnections closer to the subscriber in both telephone and cable plants. Fiber-opticcommunication, while only recently being used in fiber to the premises and fiber tothe curb schemes, has played a crucial role in enabling Broadband Internet accessby making transmission of information over larger distances much more cost-effective than copper wire technology. In a few areas not served by cable or ADSL,community organizations have begun to install Wi-Fi networks, and in some citiesand towns local governments are installing municipal Wi-Fi networks. As of 2006,high speed mobile Internet access has become available at the consumer level insome countries, using the HSDPA and EV-DO technologies. The newest technologybeing deployed for mobile and stationary broadband access is WiMAX. 6
  7. 7. Multilinking Modems It is possible to roughly double dial-up capability with multilinking technology.What is required are two modems, two phone lines, two dial-up accounts, and ISPsupport for multilinking, or special software at the user end. This option was popularwith some high-end users before ISDN, DSL and other technologies becameavailable.Diamond and other vendors had created dual phone line modems with bondingcapability. The speed of dual line modems is faster than 90 kbit/s. To use thismodem, the ISP should support line bonding. The Internet and phone charge will betwice the ordinary dial-up charge.Load Balancing takes two internet connections and feeds them into your network asone double speed, more resilient internet connection. By choosing two independentinternet providers the load balancing hardware will automatically use the line withleast load which means should one line fail, the second one automatically takes upthe slack.ISDN Integrated Service Digital Network (ISDN) is one of the oldest high-speeddigital access methods for consumers and businesses to connect to the Internet. It isa telephone data service standard. Its use in the United States peaked in the late1990s prior to the availability of DSL and cable modem technologies. Broadbandservice is usually compared to ISDN-BRI because this was the standard high-speedaccess technology that formed a baseline for the challenges faced by the earlybroadband providers. These providers sought to compete against ISDN by offeringfaster and cheaper services to consumers. A basic rate ISDN line (known as ISDN-BRI) is an ISDN line with 2 data"bearer" channels (DS0 - 64 kbit/s each). Using ISDN terminal adapters (erroneouslycalled modems), it is possible to bond together 2 or more separate ISDN-BRI lines toreach speeds of 256 kbit/s or more. The ISDN channel bonding technology has beenused for video conference applications and high-speed data transmission.Primary rate ISDN, known as ISDN-PRI, is an ISDN line with 23 DS0 channels andtotal speed of 1,544 kbit/s (US standard). ISDN E1 (European standard) line is an 7
  8. 8. ISDN lines with 30 DS0 channels and total speed of 2,048 kbit/s. Because ISDN is atelephone-based product, a lot of the terminology and physical aspects of the lineare shared by the ISDN-PRI used for voice services. An ISDN line can therefore be"provisioned" for voice or data and many different options, depending on theequipment being used at any particular installation, and depending on the offeringsof the telephone companys central office switch. Most ISDN-PRIs are used fortelephone voice communication using large PBX systems, rather than for data. Oneobvious exception is that ISPs usually have ISDN-PRIs for handling ISDN data andmodem calls.It is mainly of historical interest that many of the earlier ISDN data lines used 56 kbit/s rather than 64 kbit/s "B" channels of data. This caused ISDN-BRI to be offered atboth 128 kbit/s and 112 kbit/s rates, depending on the central offices switchingequipment.Wired EthernetWhere available, this method of broadband connection to the Internet would indicatethat the Internet access is very fast. However, just because Ethernet is offereddoesnt mean that the full 10, 100, or 1000 Mbit/s connection is able to be utilized fordirect Internet access. In a college dormitory for example, the 100 Mbit/s Ethernetaccess might be fully available to on-campus networks, but Internet access speedsmight be closer to 4xT-1 speed (6 Mbit/s). If you are sharing a broadband connectionwith others in a building, the access speed of the leased line into the building wouldof course govern the end-users speed.However, in certain locations, true Ethernet broadband access might be available.This would most commonly be the case at a POP or a datacenter, and not at atypical residence or business. When Ethernet Internet access is offered, it could befiber-optic or copper twisted pair, and the speed will conform to standard Ethernetspeeds of up to 10 Gbit/s. The primary advantage is that no special hardware isneeded for Ethernet. Ethernet also has a very low latency.Rural broadband One of the great challenges of broadband is to provide service to potentialcustomers in areas of low population density, such as to farmers and ranchers. Incities where the population density is high, it is easy for a service provider to recover 8
  9. 9. equipment costs, but each rural customer may require expensive equipment to getconnected. A similar problem existed a century ago when electrical power wasinvented. Cities were the first to receive electric lighting, as early as 1880, while inthe United States some remote rural areas were still not electrified until the 1940s,and even then only with the help of federally funded programs like the TennesseeValley Authority (TVA).Several rural broadband solutions exist, though each has its own pitfalls andlimitations. Some choices are better than others, but are dependent on howproactive the local phone company is about upgrading their rural technology.Wireless Internet Service Provider (WISPs) are rapidly becoming a popularbroadband option for rural areas.Satellite Internet This employs a satellite in geostationary orbit to relay data from the satellitecompany to each customer. Satellite Internet is usually among the most expensiveways of gaining broadband Internet access, but in rural areas it may only competewith cellular broadband. However, costs have been coming down in recent years tothe point that it is becoming more competitive with other high-speed options.Satellite Internet also has a high latency problem caused by the signal having totravel 35,000 km (22,000 miles) out into space to the satellite and back to Earthagain. The signal delay can be as much as 500 milliseconds to 900 milliseconds,which makes this service unsuitable for applications requiring real-time user inputsuch as certain multiplayer Internet games and first-person shooters played over theconnection. Despite this, it is still possible for many games to be played, but thescope is limited to real-time strategy or turn-based games. The functionality of liveinteractive access to a distant computer can also be subject to the problems causedby high latency. These problems are more than tolerable for just basic email accessand web browsing and in most cases are barely noticeable. There is no simple way to get around this problem. The delay is primarily dueto the speed of light being only 300,000 km/second (186,000 miles per second).Even if all other signaling delays could be eliminated it still takes the electromagnetic 9
  10. 10. wave 233 milliseconds to travel from ground to the satellite and back to the ground, atotal of 70,000 km (44,000 miles) to travel from you to the satellite company.Since the satellite is usually being used for two-way communications, the totaldistance increases to 140,000 km (88,000 miles), which takes a radio wave 466 msto travel. Factoring in normal delays from other network sources gives a typicalconnection latency of 500-700 ms. This is far worse latency than even most dial-upmodem users experience, at typically only 150-200 ms total latency. Most satellite Internet providers also have a FAP (Fair Access Policy).Perhaps one of the largest cons against satellite Internet, these FAPs usually throttlea users throughput to dial-up speeds after a certain "invisible wall" is hit (usuallyaround 200 MB a day). This FAP usually lasts for 24 hours after the wall is hit, and ausers throughput is restored to whatever tier they paid for. This makes bandwidth-intensive activities nearly impossible to complete in a reasonable amount of time(examples include P2P and newsgroup binary downloading).Cellular broadbandCellular phone towers are very widespread, and as cellular networks move to thirdgeneration (3G) networks they can support fast data; using technologies such asEVDO, HSDPA and UMTS.These can give broadband access to the Internet, with or without a cell phonebecause Cardbus, ExpressCard, and USB cellular modems are available, as arecellular broadband routers, which allow more than one computer to be connected tothe Internet using one cellular connection.Advantages1. The only broadband connection available on many cell phones and PDAs2. Mobile wireless connection to the Internet3. Available in all metropolitan areas, most large cities, and along majorhighways. (See a map)4. No need to aim an antenna in most cases5. The antenna is extremely small compared to a satellite dish6. Low latency compared to satellite Internet7. Higher availability than WiFi "Hot Spots"8. A traveler who already has cellular broadband will not need to pay differentWiFi Hot Spot providers for access. 10
  11. 11. Power-line InternetThis is a new service still in its infancy that may eventually permit broadband Internetdata to travel down standard high-voltage power lines. However, the system has anumber of complex issues, the primary one being that power lines are inherently avery noisy environment. Every time a device turns on or off, it introduces a pop orclick into the line. Energy-saving devices often introduce noisy harmonics into theline. The system must be designed to deal with these natural signaling disruptionsand work around them.Broadband over power lines (BPL), also known as Power line communication, hasdeveloped faster in Europe than in the US due to a historical difference in powersystem design philosophies. Nearly all large power grids transmit power at highvoltages in order to reduce transmission losses, then near the customer use step-down transformers to reduce the voltage. Since BPL signals cannot readily passthrough transformers, repeaters must be attached to the transformers. In the US, it iscommon for a small transformer hung from a utility pole to service a single house. InEurope, it is more common for a somewhat larger transformer to service 10 or 100houses. For delivering power to customers, this difference in design makes littledifference, but it means delivering BPL over the power grid of a typical US city willrequire an order of magnitude more repeaters than would be required in acomparable European city.The second major issue is signal strength and operating frequency. The system isexpected to use frequencies in the 10 to 30 MHz range, which has been used fordecades by licensed amateur radio operators, as well as international shortwavebroadcasters and a variety of communications systems (military, aeronautical, etc.).Power lines are unshielded and will act as transmitters for the signals they carry, andhave the potential to completely wipe out the usefulness of the 10 to 30 MHz rangefor shortwave communications purposes.Wireless ISP This typically employs the current low-cost 802.11 Wi-Fi radio systems to linkup remote locations over great distances, but can use other higher-power radiocommunications systems as well. 11
  12. 12. Traditional 802.11b was licensed for omni directional service spanning only 100-150meters (300-500 ft). By focusing the signal down to a narrow beam with a Yagiantenna it can instead operate reliably over a distance of many miles.Rural Wireless-ISP installations are typically not commercial in nature and areinstead a patchwork of systems built up by hobbyists mounting antennas on radiomasts and towers, agricultural storage silos, very tall trees, or whatever other tallobjects are available. There are currently a number of companies that provide thisservice. A wireless Internet access provider map for USA is publicly available forWISPS.iBlastiBlast was the brand name for a theoretical high-speed (7 Mbit/s), one-way digitaldata transmission technology from Digital TV station to users that was developedbetween June 2000 to October 2005.WorldSpaceWorldSpace is a digital satellite radio network based in Washington DC. It coversmost of Asia and Europe plus all of Africa by satellite. Beside the digital audio, usercan receive one way high speed digital data transmission (150 Kilobit/second) fromthe Satellite.PricingTraditionally, ISPs have used an "all you can eat" or flat rate model, with pricingdetermined by the maximum bitrate chosen by the customer. However the use ofhigh bandwidth applications is increasing rapidly, with increased consumer demandfor streaming content such as video on demand, as well as peer-to-peer file sharing.For ISPs who are bandwidth limited, the "all you can eat" model may becomeunsustainable as demand for bandwidth increases. Fixed costs represent 80-90% ofthe cost of providing broadband service, and although most ISPs keep their costsecret, the total cost (January 2008) is estimated to be about $0.10 per gigabyte.Currently about 5% of users consume about 50% of the total bandwidth.Some ISPs have begun experimenting with usage based pricing, notably a TimeWarner test in Beaumont, Texas. Bell Canada has imposed bandwidth caps oncustomers, with pricing ranging from $1 to $7.50 per gigabyte for usage over certain 12
  13. 13. limits. For comparison, note that a typical standard-definition movie is 700mb-1.2GB,while a high-definition movie is 6GB-12GB. This could conceivably result in a chargeof $90 to view a movie.Broadband worldwideBroadband technologies Fiber-optic communication List of device bandwidths Public switched telephone network (PSTN) Baseband Narrowband Local loopBack-channel, a low-speed, or less-than-optimal, transmission channel in theopposite direction to the main channelBroadband implementations Digital Subscriber Line (DSL), digital data transmission over the wires used inthe local loop of a telephone network Local Multipoint Distribution Service, broadband wireless access technologythat uses microwave signals operating between the 26 GHz and 29 GHz bands WiMAX, a standards-based wireless technology that provides high-throughputbroadband connections over long distances Power line communication, wireline technology using the current electricitynetworks Satellite Internet access Cable modem, designed to modulate a data signal over cable televisioninfrastructure Fiber to the premises, based on fiber-optic cables and associated opticalelectronics High-Speed Downlink Packet Access (HSDPA), a new mobile telephonyprotocol, sometimes referred to as a 3.5G (or "3½G") technology Evolution-Data Optimized (EVDO), is a wireless radio broadband datastandard adopted by many CDMA mobile phone service providers 13
  14. 14. Future broadband implementations White Spaces Coalition a group of technology companies aiming to deliverbroadband internet access via unused analog television frequenciesBroadband applications Broadband telephony Broadband radio 14
  15. 15. CHAPTER 3LITRATURE REVIEW 15
  16. 16. INDIAN BROADBAND MARKETThe telecom world may still be marveling at Indias mobile telephony growth, whichat 100 million connections has emerged as the fastest growing in the world, but theother scorching growth story in the countrys telecom sector could well be broadbandover wireless.Thats the conclusion Canada-based broadband telecom research firm MaravedisInc. and its Indian counterpart Tonse Telecom arrived at in their just released reporton the Indian broadband market.The report forecasts that the next phenomenal telecom growth story in India lies inbroadband wireless access (BWA) segment, which could experience the sameexplosive growth as mobile telephony experienced over the last three years."Our analysis of the Indian broadband market has revealed that although broadbandhas seen grown quite a bit in the past year it has seen nothing yet," said AdlaneFellah, CEO and founder of Maravedis, that claims to be a world leader in marketresearch and analysis of the global broadband, BWA and WiMax markets. “But if India can bring in the right conditions, broadband, particularly overwireless access, would follow the same explosion as mobile phones experienced inIndia lately."The mobile phone made its debut in the country in 1995 and struggled for the firstthree years to touch the 1 million mark in 1998. Growth started perking up thereafterto reach 3 million in 2000, 5 million in 2001, and 10 million in 2002.But finally due to a variety of reasons like a new telecom policy that removed theproblems of mobile operators and the crashing of handset prices, mobile telecomsubscription exploded in the country to reach 100 million in June 2006.And now, analysts even project that Indias monthly net mobile subscriber additionscould overtake those of China in the next few months. China added 5.6 millionmobile subscribers in May, while Indias mobile-phone subscriber base grew by 4.25million (June figures not released yet) that month.However, according to Sridhar Pai, the co-author of the report, to achieve that kind ofgrowth the Indian government has to take the first steps, which are opening up thespectrum-radio waves that carry the voice/data- for WiMax so that broadband can 16
  17. 17. proliferate over wireless using specifically the WiMax technology, and formulatespolicies so that prices of end user equipments -- like computers and modems -- fallto make them more affordable for Indians.WiMax is defined as Worldwide Interoperability for Microwave Access. It is astandards-based wireless technology that provides high-throughput broadbandconnections over long distances. WiMax can be used for a number of applications,including "last mile" broadband connections, hotspots and cellular backhaul, andhigh-speed enterprise connectivity for business.Broadband services were launched in India in 2005 and now cover about 300 Indiancities with a combined 1.5 million connections. But even as wireless telephony wasgrowing at scorching rate then, India chose to introduce broadband using the ADSLor asymmetric digital subscriber line technology that basically uses existing coppertelephone lines thus restricting its data transfer speed and reach."In a country as congested as India the ADSL technology can only grow to a certainextent," Pai said, "and in fact it has already reached saturation."Which is why, even as 1.5 million broadband connections in about a year lookreasonably satisfactory by Indian standards, the number is piffling considering thatIndia now has 50 million fixed line and 100 million mobile users, said the report.However, while low broadband penetration is a clear opportunity, its main hurdle isavailability of spectrum. Currently, telecom operators and the government areengaged in a war over spectrum allocation. While the operators are clamoring formore spectrum for expansion and improvement their quality of services, thegovernment that "owns" most the spectrum through the countrys space and defensesectors, is still undecided on how to allocate this scare resource.The report said that even if the government has recently announced allocation ofspectrum on the 3.3 to 3.4 GHz band range, the country needs 3.4 to 3.5 GHz --which is the WiMax spectrum -- for a profitable business case.Meanwhile activity in the broadband wireless access space seems to be hecticalready, in anticipation of the government announcing its new spectrum allocationpolicy expected by the year end.For instance, five Indian operators, Bharti TeleVentures, Reliance Telecom, theNASDAQ-listed SIFY Ltd, the state-owned BSNL and Tata Group-owned VSNL haveacquired Broadband wireless licenses in 3.3 GHz range and are in various stages oftrials. 17
  18. 18. The report says that VSNL has also announced Phase 1 pre-WiMax deploymentalthough there is clearly insufficient spectrum.Global telecom companies too have joined the fray. Intel is reportedly making"significant progress" in working closely with the Indian government in bringing thecountrys rural broadband goals to reality, while Motorola is strengthening itspresence in the hinterlands through its extensive broadband wireless access projectsfor state governments.Alcatel has joined the bandwagon too by entering into a joint venture recently with agovernment-owned telecom research outfit to focus on exclusive BWA/WiMaxsolutions that are tailor made for India "at Indian price points.""Although the Indian broadband arena is emerging, it offers huge potential for thosethat can demonstrate perseverance, patience and commitment," said the report,which has projected that assuming India releases WiMax spectrum by this year end,the annual BWA/WiMax equipment market opportunity -- a mere $6 million in 2005 --could increase to $256 million in 2012."By then India could have accumulated 18 million BWA subscribers making thecountry one of the top three WiMax markets in the world,"Special reference to rural broadband One of the great challenges of broadband is to provide service to potentialcustomers in areas of low population density, such as to farmers and ranchers. Incities where the population density is high, it is easy for a service provider to recoverequipment costs, but each rural customer may require expensive equipment to getconnected.Several rural broadband solutions exist, though each has its own pitfalls andlimitations. Some choices are better than others, but are dependent on howproactive the local phone company is about upgrading their ruraltechnology.Wireless Internet Service Provider (WISPs) are rapidly becoming apopular broadband option for rural areas.According to the report in November provided by Voice and data magazine ruralbroadband area has been referred to as Gold Mines for resources and revenues andmajor service providers instead of taking governments help have offered government 18
  19. 19. to help out in the successful implementation of broadband in Rural India withspecialattention to the areas ofa) Healtcareb) EducationC) Entertainment-IPTV, Gaming, Video Streaming serversd) Communication-VOIPAll these is not possible without the successful implementation of Broad band inIndia hence concluding we can say that with growth and progress of the economy inIndia Broadband is is the underlying need which has been well understood ,hencethere lies a huge potencial market and technology for the success of broadband.WiMAX WiMAX, the Worldwide Interoperability for Microwave Access, is atelecommunications technology aimed at providing wireless data over long distancesin a variety of ways, from point-to-point links to full mobile cellular type access. It isbased on the IEEE 802.16 standard, which is also called WirelessMAN. The name"WiMAX" was created by the WiMAX Forum, which was formed in June 2001 topromote conformance and interoperability of the standard. The forum describesWiMAX as "a standards-based technology enabling the delivery of last mile wirelessbroadband access as an alternative to cable and DSL" (and also to HSPA).Uses The bandwidth and reach of WiMAX make it suitable for the following potentialapplications:Connecting Wi-Fi hotspots with each other and to other parts of the Internet. Providing a wireless alternative to cable and DSL for last mile broadbandaccess. Providing high-speed data and telecommunications services. Providing a diverse source of Internet connectivity as part of a businesscontinuity plan. That is, if a business has a fixed and a wireless Internet connection, 19
  20. 20. especially from unrelated providers, they are unlikely to be affected by the sameservice outage. Providing nomadic connectivity.Broadband accessMany companies are closely examining WiMAX for "last mile" connectivity at highdata rates. The resulting competition may bring lower pricing for both home andbusiness customers or bring broadband access to places where it has beeneconomically unavailable. Prior to WiMAX, many operators have been usingproprietary fixed wireless technologies for broadband services.WiMAX access was used to assist with communications in Aceh, Indonesia, after thetsunami in December 2004. All communication infrastructure in the area, other thanHam Radio, was destroyed, making the survivors unable to communicate withpeople outside the disaster area and vice versa. WiMAX provided broadband accessthat helped regenerate communication to and from Aceh.WiMAX was used by Intel to assist the FCC and FEMA in their communicationsefforts in the areas affected by Hurricane Katrina.Subscriber unitsWiMAX subscriber units are available in both indoor and outdoor versions fromseveral manufacturers. Self-install indoor units are convenient, but radio lossesmean that the subscriber must be significantly closer to the WiMAX base station thanwith professionally-installed external units. As such, indoor-installed units require amuch higher infrastructure investment as well as operational cost (site lease,backhaul, maintenance) due to the high number of base stations required to cover agiven area. Indoor units are comparable in size to a cable modem or DSL modem.Outdoor units are roughly the size of a laptop PC, and their installation is comparableto a residential satellite dish.With the advent of mobile WiMAX, there is an increasing focus on portable units.This includes handsets (similar to cellular smartphones) and PC peripherals (PCCards or USB dongles). In addition, there is much emphasis from operators onconsumer electronics devices (game terminals, MP3 players and the like); it isnotable this is more similar to Wi-Fi than 3G cellular technologies.Mobile handset applications 20
  21. 21. Some cellular companies are evaluating WiMAX as a means of increasing bandwidthfor a variety of data-intensive applications.Sprint Nextel announced in mid-2006 that it would invest about US$ 5 billion in a WiMAX technology buildout over the next few years.[3] As of November 9,2007 this project in partnership with Clearwire has been shelved, but the projectcould be revived with or without Clearwire now that Sprint has hired Dan Hesse asits new CEO. On December 5, 2007, Bin Shen, Sprints VP of Product Managementand Partnership Development, announced that Sprints WiMAX network will go live ina soft launch in Chicago, Baltimore, and Washington DC. Full commercial launch isstill expected to be approximately spring of 2008. NYT reports that Sprints softlaunch in the three test markets went live as of January 11, 2008. Sprint hopes touse WiMAX as a springboard past its competitors and past concerns about itsshrinking user base and concerns about the financial wisdom of the large WiMAXdeployment.Backhaul/access network applications WiMAX is a possible replacement candidate for cellular phone technologiessuch as GSM and CDMA, or can be used as a layover to increase capacity. It hasalso been considered as a wireless backhaul technology for 2G, 3G, and 4Gnetworks in both developed and developing nations."Backhaul" for remote cellular operations is typically provided via satellite, and inurban areas via one or several T1 connections. WiMAX is mobile broadband and assuch has much more substantial backhaul need. Therefore traditional backhaulsolutions are not appropriate. Consequently the role of very high capacity wirelessmicrowave point-to-point backhaul (200 or more Mbit/s with typically 1 ms or lessdelay) is on the rise. Also fiber backhaul is more appropriate. Deploying WiMAX in rural areas with limited or no internet backbone will bechallenging as additional methods and hardware will be required to procure sufficientbandwidth from the nearest sources -- the difficulty being in proportion to thedistance between the end-user and the nearest sufficient internet backbone.Given the limited wired infrastructure in some developing countries, the costs toinstall a WiMAX station in conjunction with an existing cellular tower or even as a 21
  22. 22. solitary hub are likely to be small in comparison to developing a wired solution. Areasof low population density and flat terrain are particularly suited to WiMAX and itsrange. For countries that have skipped wired infrastructure as a result of prohibitivecosts and unsympathetic geography, WiMAX can enhance wireless infrastructure inan inexpensive, decentralized, deployment-friendly and effective manner.Technical information WiMAX is a term coined to describe standard, interoperable implementationsof IEEE 802.16 wireless networks, similar to the way the term Wi-Fi is used forinteroperable implementations of the IEEE 802.11 Wireless LAN standard. However,WiMAX is very different from Wi-Fi in the way it works.MAC layer/data link layer In Wi-Fi the media access controller (MAC) uses contention access — allsubscriber stations that wish to pass data through a wireless access point (AP) arecompeting for the APs attention on a random interrupt basis. This can causesubscriber stations distant from the AP to be repeatedly interrupted by closerstations, greatly reducing their throughput. This makes services such as Voice overIP (VoIP) or IPTV, which depend on an essentially-constant Quality of Service (QoS)depending on data rate and interruptibility, difficult to maintain for more than a fewsimultaneous users.In contrast, the 802.16 MAC uses a scheduling algorithm for which the subscriberstation need compete once (for initial entry into the network). After that it is allocatedan access slot by the base station. The time slot can enlarge and contract, butremains assigned to the subscriber station, which means that other subscriberscannot use it. In addition to being stable under overload and over-subscription(unlike 802.11), the 802.16 scheduling algorithm can also be more bandwidthefficient. The scheduling algorithm also allows the base station to control QoSparameters by balancing the time-slot assignments among the application needs ofthe subscriber stations.Physical layer 22
  23. 23. The original version of the standard on which WiMAX is based (IEEE 802.16)specified a physical layer operating in the 10 to 66 GHz range. 802.16a, updated in2004 to 802.16-2004, added specifications for the 2 to 11 GHz range. 802.16-2004was updated by 802.16e-2005 in 2005 and uses scalable orthogonal frequency-division multiple access (SOFDMA) as opposed to the OFDM version with 256 sub-carriers (of which 200 are used) in 802.16d. More advanced versions, including802.16e, also bring Multiple Antenna Support through Multiple-input multiple-outputcommunications (MIMO) See WiMAX MIMO. This brings potential benefits in termsof coverage, self installation, power consumption, frequency re-use and bandwidthefficiency. 802.16e also adds a capability for full mobility support. The WiMAXcertification allows vendors with 802.16d products to sell their equipment as WiMAXcertified, thus ensuring a level of interoperability with other certified products, as longas they fit the same profile.Most commercial interest is in the 802.16d and .16e standards, since the lowerfrequencies used in these variants suffer less from inherent signal attenuation andtherefore give improved range and in-building penetration. Already today, a numberof networks throughout the world are in commercial operation using certified WiMAXequipment compliant with the 802.16d standard. 23
  24. 24. ArchitectureThe WiMAX Forum has defined an architecture that defines how a WiMAX networkconnects with other networks, and a variety of other aspects of operating such anetwork, including address allocation, authentication, etc. An overview of thearchitecture is given in the illustration. This defines the following components:SS/MS: the Subscriber Station/Mobile Station ASN: the Access Service Network BS: Base station, part of the ASNASN-GW: the ASN Gateway, part of the ASNCSN: the Connectivity Service Network HA: Home Agent, part of the CSN AAA: AAA Server, part of the CSN NAP: a Network Access Provider 24
  25. 25. NSP: a Network Service Providerplus a number of interconnections (or reference points) between these, labeled R1 toR5 and R8.Its important to note that the functional architecture can be designed into varioushardware configurations rather than fixed configurations. For example, thearchitecture is flexible enough to allow remote/mobile stations of varying scale andfunctionality and Base Stations of varying size - e.g. femto, pico, and mini BS as wellas macros.Comparison with Wi-Fi Possibly due to the fact both WiMAX and Wi-Fi begin with the same twoletters, are based upon IEEE standards beginning with "802.", and both have aconnection to wireless connectivity and the Internet, comparisons and confusionbetween the two are frequent. Despite this, the two standards are aimed at differentapplications. WiMAX is a long-range system, covering many kilometers that typically useslicensed spectrum (although it is also possible to use unlicensed spectrum) to delivera point-to-point connection to the Internet from an ISP to an end user. Different802.16 standards provide different types of access, from mobile (similar to dataaccess via a cellphone) to fixed (an alternative to wired access, where the end userswireless termination point is fixed in location.) Wi-Fi is a shorter range system, typically hundreds of meters, that usesunlicensed spectrum to provide access to a network, typically covering only thenetwork operators own property. Typically Wi-Fi is used by an end user to accesstheir own network, which may or may not be connected to the Internet. If WiMAXprovides services analogous to a cellphone, Wi-Fi is more analogous to a cordlessphone. WiMAX and Wi-Fi have quite different Quality of Service (QoS)mechanisms. WiMAX uses a mechanism based on setting up connections betweenthe Base Station and the user device. Each connection is based on specificscheduling algorithms, which means that QoS parameters can be guaranteed for 25
  26. 26. each flow. Wi-Fi has introduced a QoS mechanism similar to fixed Ethernet, wherepackets can receive different priorities based on their tags. This means that QoS isrelative between packets/flows, as opposed to guaranteed. WiMAX is highly scalable from what are called "femto"-scale remotestations to multi-sector maxi scale base that handle complex tasks of managementand mobile handoff functions and include MIMO-AAS smart antenna subsystems.Due to the ease and low cost with which Wi-Fi can be deployed, it is sometimesused to provide Internet access to third parties within a single room or buildingavailable to the provider, often informally, and sometimes as part of a businessrelationship. For example, many coffee shops, hotels, and transportation hubscontain Wi-Fi access points providing access to the Internet for customers.Spectrum allocation issues The 802.16 specification applies across a wide swath of the RF spectrum,and WiMAX could function on any frequency below 66 GHz, (higher frequencieswould decrease the range of a Base Station to a few hundred meters in an urbanenvironment).There is no uniform global licensed spectrum for WiMAX, although the WiMAXForum has published three licensed spectrum profiles: 2.3 GHz, 2.5 GHz and 3.5GHz, in an effort to decrease cost: economies of scale dictate that the more WiMAXembedded devices (such as mobile phones and WiMAX-embedded laptops) areproduced, the lower the unit cost. (The two highest cost components of producing amobile phone are the silicon and the extra radio needed for each band.) Similareconomy of scale benefits apply to the production of Base Stations. In the unlicensed band, 5.x GHz is the approved profile. Telecomcompanies are unlikely to use this spectrum widely other than for backhaul, as theydo not own and control the spectrum. In the USA, the biggest segment available is around 2.5 GHz, and is alreadyassigned, primarily to Sprint Nextel and Clearwire. Elsewhere in the world, the most-likely bands used will be the Forum approved ones, with 2.3 GHz probably beingmost important in Asia. Some countries in Asia like India and Indonesia will use amix of 2.5 GHz, 3.3 GHz and other frequencies. 26
  27. 27. Analog TV bands (700 MHz) may become available for WiMAX use, butawait the complete rollout of digital TV, and there will be other uses suggested forthat spectrum. In the USA the FCC auction for this spectrum began in January 2008and, as a result, the biggest share of the spectrum went to Verizon Wireless and thenext biggest to AT&T. EU commissioner Viviane Reding has suggested re-allocationof 500–800 MHz spectrum for wireless communication, including WiMAX. WiMAX profiles define channel size, TDD/FDD and other necessaryattributes in order to have inter-operating products. The current fixed profiles aredefined for both TDD and FDD profiles. At this point, all of the mobile profiles areTDD only. The fixed profiles have channel sizes of 3.5 MHz, 5 MHz, 7 MHz and 10MHz. The mobile profiles are 5 MHz, 8.75 MHz and 10 MHz. (Note: the 802.16standard allows a far wider variety of channels, but only the above subsets aresupported as WiMAX profiles.) Since October 2007, the Radiocommunication Sector of the InternationalTelecommunication Union (ITU-R) has decided to include WiMAX technology in theIMT-2000 set of standards. This enables spectrum owners (specifically in the2.5-2.69 GHz band at this stage) to use Mobile WiMAX equipment in any countrythat recognizes the IMT-2000.Spectral efficiencyOne of the significant advantages of advanced wireless systems such as WiMAX isspectral efficiency. For example, 802.16-2004 (fixed) has a spectral efficiency of 3.7(bit/s)/Hertz, and other 3.5–4G wireless systems offer spectral efficiencies that aresimilar to within a few tenths of a percent. The notable advantage of WiMAX comesfrom combining SOFDMA with smart antenna technologies. This multiplies theeffective spectral efficiency through multiple reuse and smart network deploymenttopologies. The direct use of frequency domain organization simplifies designs usingMIMO-AAS compared to CDMA/WCDMA methods, resulting in more-effectivesystems.Silicon implementations A critical requirement for the success of a new technology is the availability oflow-cost chipsets and silicon implementations. 27
  28. 28. Intel is a leader in promoting WiMAX, and has developed its own chipset. However, itis notable that most of the major semiconductor companies have to date been morecautious of involvement and most of the solutions come from specialist smaller orstart-up suppliers. For the client-side these include ApaceWave, GCTSemiconductor, Altair Semiconductor, Beceem, Comsys, Runcom, Motorola with TI,NextWave, Sequans, Redpine signals, Wavesat, Coresonic & SySDSoft. BothSequans and Wavesat manufacture solutions for both clients and network while TI,DesignArt, and picoChip are focused on WiMAX chip sets for base stations. Thelarge number of suppliers during introduction phase of WiMAX demonstrates the lowentry barriers for IPR.Standards The current WiMAX incarnation, Mobile WiMAX, is based upon IEEE Std802.16e-2005, approved in December 2005. It is an amendment of IEEE Std802.16-2004, and so the actual standard is 802.16-2004 as amended by802.16e-2005 — the specifications need to be read together to understand them.IEEE Std 802.16-2004 addresses only fixed systems. It replaced IEEE Standards802.16-2001, 802.16c-2002, and 802.16a-2003.IEEE 802.16e-2005IEEE 802.16e-2005 improves upon IEEE 802.16-2004 by: Adding support for mobility (soft and hard handover between base stations).This is seen as one of the most important aspects of 802.16e-2005, and is the verybasis of Mobile WiMAX. Scaling of the Fast Fourier Transform (FFT) to the channel bandwidth inorder to keep the carrier spacing constant across different channel bandwidths(typically 1.25 MHz, 5 MHz, 10 MHz or 20 MHz). Constant carrier spacing results ina higher spectrum efficiency in wide channels, and a cost reduction in narrowchannels. Also known as Scalable OFDMA (SOFDMA). Other bands not multiples of1.25 MHz are defined in the standard, but because the allowed FFT subcarriernumbers are only 128, 512, 1024 and 2048, other frequency bands will not haveexactly the same carrier spacing, which might not be optimal for implementations. Improving NLOS coverage by utilizing advanced antenna diversityschemes, and hybrid-Automatic Retransmission Request (HARQ) 28
  29. 29. Improving capacity and coverage by introducing Adaptive Antenna Systems(AAS) and Multiple Input Multiple Output (MIMO) technology Increasing system gain by use of denser sub-channelization, thereby improvingindoor penetration Introducing high-performance coding techniques such as Turbo Coding andLow-Density Parity Check (LDPC), enhancing security and NLOS performance Introducing downlink sub-channelization, allowing administrators to tradecoverage for capacity or vice versa Enhanced Fast Fourier Transform algorithm can tolerate larger delayspreads, increasing resistance to multipath interference .Adding an extra QoS class(enhanced real-time Polling Service) more appropriate for VoIP applications.802.16d vendors point out that fixed WiMAX offers the benefit of availablecommercial products and implementations optimized for fixed access. It is a popularstandard among alternative service providers and operators in developing areas dueto its low cost of deployment and advanced performance in a fixed environment.Fixed WiMAX is also seen as a potential standard for backhaul of wireless basestations such as cellular, Wi-Fi or even Mobile WiMAX. SOFDMA (used in 802.16e-2005) and OFDM256 (802.16d) are notcompatible so most equipment will have to be replaced if an operator wants or needsto move to the later standard. However, some manufacturers are planning to providea migration path for older equipment to SOFDMA compatibility which would ease thetransition for those networks which have already made the OFDM256 investment.Intel provides a dual-mode 802.16-2004 802.16-2005 chipset for subscriber units.This affects a relatively small number users and operators.3G and 4G cellular phone systemsBoth major 3G systems, CDMA2000 and UMTS, compete with WiMAX. Both aim tooffer DSL-class Internet access in addition to phone service. UMTS has also beenenhanced to compete directly with WiMAX in the form of UMTS-TDD, which can useWiMAX oriented spectrum and provides a more consistent, if lower bandwidth atpeak, user experience than WiMAX. 29
  30. 30. 3G cellular phone systems usually benefit from already having entrenchedinfrastructure, being upgraded from earlier systems. Users can usually fall back toolder systems when they move out of range of upgraded equipment, often relativelyseamlessly.The major cellular standards are being evolved to so-called 4G, high bandwidth, lowlatency, all-IP networks with voice services built on top. With GSM/UMTS, the moveto 4G is the 3GPP Long Term Evolution effort. For AMPS/TIA derived standardssuch as CDMA2000, a replacement called Ultra Mobile Broadband is underdevelopment. In both cases, existing air interfaces are being discarded, in favour ofOFDMA for the downlink and a variety of OFDM based solutions for the uplink, muchakin to WiMAX.In some areas of the world the wide availability of UMTS and a general desire forstandardization has meant spectrum has not been allocated for WiMAX: in July2005, the EU-wide frequency allocation for WiMAX was blocked.Mobile Broadband Wireless AccessMobile Broadband Wireless Access (MBWA) is a technology being developed byIEEE 802.20 and is aimed at wireless mobile broadband for operations from 120 to350 km/h. The 802.20 standard committee was first to define many of the methodswhich were later funneled into Mobile WiMAX, including high speed dynamicmodulation and similar scalable OFDMA capabilities. It apparently retains fast hand-off, Forward Error Correction (FEC) and cell edge enhancements.The Working Group was temporarily suspended in mid 2006 by the IEEE-SAStandards Board since it had been the subject of a number of appeals, and apreliminary investigation of one of these "revealed a lack of transparency, possibledominance, and other irregularities in the Working Group".In September 2006 the IEEE-SA Standards Board approved a plan to enable theworking group to continue under new conditions, and the standard is now expectedto be finalized by Q2 2008.Internet-oriented systemsEarly WirelessMAN standards, the European standard HIPERMAN and Koreanstandard WiBro have been harmonized as part of WiMAX and are no longer seen ascompetition but as complementary. All networks now being deployed in South Korea,the home of the Wibro standard, are now WiMAX. 30
  31. 31. As a short-range mobile Internet solution, such as in cafes and at transportationhubs like airports, the popular Wi-Fi 802.11b/g system is widely deployed, andprovides enough coverage for some users to feel subscription to a WiMAX service isunnecessary.ComparisonThe following table should be treated with caution as it only shows peak rates whichare potentially very misleading. In addition the comparisons listed are not normalizedby physical channel size (i.e. spectrum used to achieve the listed peak rates); thisobfuscates spectral efficiency and net through-put capabilities of the differentwireless technologies listed below.Competing technologies Comparison of Mobile Internet Access methods Uplin Downli Primary k Standard Family Radio Tech nk Notes Use (Mbit/ (Mbit/s) s) Quoted speeds only achievable at Mobile MIMO- very short 802.16e WiMAX 70 70 Internet SOFDMA ranges, more practically 10 Mbit/s at 10 km. HIPERMA Mobile HIPERMAN OFDM 56.9 56.9 N Internet 31
  32. 32. Mobile Inter Mobile rangeWiBro WiBro OFDMA 50 50 net (900 m) HC- iBurst Mobile InteriBurst SDMA/TDD/MI 64 64 3–12 km 802.20 net MOEDGE Mobile Inter 3GPP GSM TDMA/FDD 1.9 0.9Evolution net Release 7 HSDPA widely deployed. TypicalUMTS W- CDMA/FDD downlinkCDMA 0.384 0.384 UMTS/3G Mobile rates todayHSDPA+HS 14.4 5.76 SM phone CDMA/FDD/MI 1–2 Mbit/s,UPA 42 11.5 MO ~200 kbit/sHSPA+ uplink; future downlink up to 28.8 Mbit/ s.UMTS-TDD UMTS/3G Mobile CDMA/TDD 16 16 Reported SM Internet speeds according to IPWireless using 16QAM modulation similar to HSDPA+HS 32
  33. 33. UPA OFDMA/MIMO Still in UMTS/4G LTE UMTS General 4G /SC-FDMA >100 >50 development SM (HSOPA) Succeeded by EV-DO CDMA200 Mobile 1xRTT CDMA 0.144 0.144 0 phone Rev B note: N is the EV-DO 1x R number of ev. 0 1.25 MHz 2.45 0.15 EV-DO 1x R CDMA200 Mobile chunks of CDMA/FDD 3.1 1.8 ev.A 0 Internet spectrum 4.9xN 1.8xN EV-DO Rev. used.Not B yetdeployed.Notes: All speeds are theoretical maximums and will vary by a number of factors,including the use of external antennae, distance from the tower and the groundspeed (e.g. communications on a train may be poorer than when standing still).Usually the bandwidth is shared between several terminals. The performance ofeach technology is determined by a number of constraints, including the spectralefficiency of the technology, the cell sizes used, and the amount of spectrumavailable. For more information.Future developmentMobile WiMAX based upon 802.16e-2005 has been accepted as IP-OFDMA forinclusion as the sixth wireless link system under IMT-2000. This can hastenacceptance by regulatory authorities and operators for use in cellular spectrum.WiMAX II, 802.16m will be proposed for IMT-Advanced 4G.The goal for the long term evolution of both WiMAX and LTE is to achieve 100 Mbit/smobile and 1 Gbit/s fixed-nomadic bandwidth as set by ITU for 4G NGMN (NextGeneration Mobile Network) systems through the adaptive use of MIMO-AAS and 33
  34. 34. smart, granular network topologies. 3GPP LTE and WiMAX-m are concentratingmuch effort on MIMO-AAS, mobile multi-hop relay networking and relateddevelopments needed to deliver 10X and higher Co-Channel reuse multiples.Since the evolution of core air-link technologies has approached the practical limitsimposed by Shannons Theorem, the evolution of wireless has embarked on pursuitof the 3X to 10X+ greater bandwidth and network efficiency by advances in thespatial and smart wireless broadband networking technologies.InterferenceA field test conducted by SUIRG (Satellite Users Interference Reduction Group) withsupport from the U.S. Navy, the Global VSAT Forum, and several memberorganizations yielded conclusive results on the incompatibility of WiMAX systemsand satellites sharing the C-band.The WiMAX Forum has not answered yet. WI-FIThe purpose of Wi-Fi is simple: Hide complexity by enabling wireless access toapplications and data, media and streams. The main aims of Wi-Fi are: enable access to information easily ensure compatibility and coexistence get rid of cabling and wiring get rid of switches, adapters, plugs and connectors.Uses 34
  35. 35. A Wi-Fi enabled device such as a PC, game console, cell phone, MP3 player orPDA can connect to the Internet when within range of a wireless network connectedto the Internet. The coverage of one or more interconnected access points — calleda hotspot — can comprise an area as small as a single room with wireless-opaquewalls or as large as many square miles covered by overlapping access points. Wi-Fitechnology has served to set up mesh networks, for example, in London.[1] Botharchitectures can operate in community networks.In addition to restricted use in homes and offices, Wi-Fi can make access publiclyavailable at Wi-Fi hotspots provided either free of charge or to subscribers to variousproviders. Organizations and businesses such as airports, hotels and restaurantsoften provide free hotspots to attract or assist clients. Enthusiasts or authorities whowish to provide services or even to promote business in a given area sometimesprovide free Wi-Fi access. Metropolitan-wide Wi-Fi (Muni-Fi) already has more than300 projects in process.[2] Wi-Fi also allows connectivity in peer-to-peer (wireless ad-hoc network)mode, which enables devices to connect directly with each other. This connectivitymode can prove useful in consumer electronics and gaming applications.When wireless networking technology first entered the market many problemsensued for consumers who could not rely on products from different vendors workingtogether. The Wi-Fi Alliance began as a community to solve this issue — aiming toaddress the needs of the end-user and to allow the technology to mature. TheAlliance created the branding Wi-Fi CERTIFIED to reassure consumers thatproducts will interoperate with other products displaying the same branding. Many consumer devices use Wi-Fi. Amongst others, personal computers cannetwork to each other and connect to the Internet, mobile computers can connect tothe Internet from any Wi-Fi hotspot, and digital cameras can transfer imageswirelessly. Routers which incorporate a DSL-modem or a cable-modem and a Wi-Fiaccess point, often set up in homes and other premises, provide Internet-access andinternetworking to all devices connected (wirelessly or by cable) to them. One canalso connect Wi-Fi devices in ad-hoc mode for client-to-client connections without arouter. 35
  36. 36. As of 2007 Wi-Fi technology had spread widely within business and industrialsites. In business environments, just like other environments, increasing the numberof Wi-Fi access-points provides redundancy, support for fast roaming and increasedoverall network-capacity by using more channels or by defining smaller cells. Wi-Fienables wireless voice-applications (VoWLAN or WVOIP). Over the years, Wi-Fiimplementations have moved toward "thin" access-points, with more of the networkintelligence housed in a centralized network appliance, relegating individual access-points to the role of mere "dumb" radios. Outdoor applications may utilize true meshtopologies. As of 2007 Wi-Fi installations can provide a secure computer networkinggateway, firewall, DHCP server, intrusion detection system, and other functions.Balancing effort, advantages and challengesAs in all aspects of life and technology arguing advantages and disadvantages is aquestion of views and aspects. The baseline must be to balance cost and benefit.There is no addressing of advantages without addressing the aspect and view on thesubject first.Operational advantagesWi-Fi allows LANs (Local Area Networks) to be deployed without cabling for clientdevices, typically reducing the costs of network deployment and expansion. Spaceswhere cables cannot be run, such as outdoor areas and historical buildings, can hostwireless LANs.As of 2007 wireless network adapters are built into most modern laptops. The priceof chipsets for Wi-Fi continues to drop, making it an economical networking optionincluded in ever more devices. Wi-Fi has become widespread in corporateinfrastructures.Different competitive brands of access points and client network interfaces are inter-operable at a basic level of service. Products designated as "Wi-Fi Certified" by theWi-Fi Alliance are backwards inter-operable. Wi-Fi is a global set of standards.Unlike mobile telephones, any standard Wi-Fi device will work anywhere in theworld.Wi-Fi is widely available in more than 220,000 public hotspots and tens of millions ofhomes and corporate and university campuses worldwide.[3] WPA is not easilycracked if strong passwords are used and WPA2 encryption has no known 36
  37. 37. weaknesses. New protocols for Quality of Service (WMM) make Wi-Fi more suitablefor latency-sensitive applications (such as voice and video), and power savingmechanisms (WMM Power Save) improve battery operation.LimitationsSpectrum assignments and operational limitations are not consistent worldwide.Most of Europe allows for an additional 2 channels beyond those permitted in theU.S. for the 2.4 GHz band. (1–13 vs. 1–11); Japan has one more on top of that (1–14). Europe, as of 2007, was essentially homogeneous in this respect. A veryconfusing aspect is the fact that a Wi-Fi signal actually occupies five channels in the2.4 GHz band resulting in only three non-overlapped channels in the U.S.: 1, 6, 11,and three or four in Europe: 1, 5, 9, 13 can be used if all the equipment on a specificarea can be granted not to use 802.11b at all, even as fallback or beacon. Equivalentisotropically radiated power (EIRP) in the EU is limited to 20 dBm (0.1 W).ReachDue to reach requirements for wireless LAN applications, power consumption is fairlyhigh compared to some other low-bandwidth standards. Especially Zigbee andBluetooth supporting wireless PAN applications refer to much lesser propagationrange of <10m (ref. e.g. IEEE Std. 802.15.4 section 1.2 scope). Range is alwaysmaking battery life a concern.Wi-Fi networks have limited range. A typical Wi-Fi home router using 802.11b or802.11g with a stock antenna might have a range of 32 m (120 ft) indoors and 95 m(300 ft) outdoors. Range also varies with frequency band. Wi-Fi in the 2.4 GHzfrequency block has slightly better range than Wi-Fi in the 5 GHz frequency block.Outdoor range with improved (directional) antennas can be several kilometres ormore with line-of-sight.Wi-Fi performance decreases roughly quadratically as the range increases atconstant radiation levels.Threats to securityThe most common wireless encryption standard, Wired Equivalent Privacy or WEP,has been shown to be easily breakable even when correctly configured. Wi-FiProtected Access (WPA and WPA2), which began shipping in 2003, aims to solve 37
  38. 38. this problem and is now available on most products. Wi-Fi Access Points typicallydefault to an "open" (encryption-free) mode. Novice users benefit from a zero-configuration device that works out of the box, but this default is without any wirelesssecurity enabled, providing open wireless access to their LAN. To turn security onrequires the user to configure the device, usually via a software graphical userinterface (GUI). Wi-Fi networks that are open (unencrypted) can be monitored andused to read and copy data (including personal information) transmitted over thenetwork, unless another security method is used to secure the data, such as a VPNor a secure web page. (See HTTPS/Secure Socket Layer.)PopulationMany 2.4 GHz 802.11b and 802.11g Access points default to the same channel oninitial startup, contributing to congestion on certain channels. To change the channelof operation for an access point requires the user to configure the device. Yet, thisdefault use of channels 1, 6 and 11 gives better performance than "advanced" userschoosing channels 2, 5, 7 and 9 as "unused, free".PollutionStandardization is a process driven by market forces. Interoperability issues betweennon-Wi-Fi brands or proprietary deviations from the standard can still disruptconnections or lower throughput speeds on all users devices that are within range,to include the non-Wi-Fi or proprietary product. Moreover, the usage of the ISM bandin the 2.45 GHz range is also common to Bluetooth, WPAN-CSS, ZigBee and anynew system will take its share.Wi-Fi pollution, or an excessive number of access points in the area, especially onthe same or neighboring channel, can prevent access and interfere with the use ofother access points by others, caused by overlapping channels in the 802.11g/bspectrum, as well as with decreased signal-to-noise ratio (SNR) between accesspoints. This can be a problem in high-density areas, such as large apartmentcomplexes or office buildings with many Wi-Fi access points. Additionally, otherdevices use the 2.4 GHz band: microwave ovens, security cameras, Bluetoothdevices and (in some countries) Amateur radio, video senders, cordless phones andbaby monitors can cause significant additional interference. General guidance tothose who suffer these forms of interference or network crowding is to migrate to a 38
  39. 39. Wi-Fi 5 GHz product, (802.11a, or the newer 802.11n if it has 5 GHz support) as the5 GHz band is relatively unused and there are many more channels available. Thisalso requires users to set up the 5 GHz band to be the preferred network in the clientand to configure each network band to a different name (SSID). It is also an issuewhen municipalities,[4] or other large entities such as universities, seek to providelarge area coverage. This openness is also important to the success and widespreaduse of 2.4 GHz Wi-Fi. 3G 3G is the third generation of mobile phone standards and technology,superseding 2G. It is based on the International Telecommunication Union (ITU)family of standards under the International Mobile Telecommunications programme,IMT-2000.3G technologies enable network operators to offer users a wider range of moreadvanced services while achieving greater network capacity through improvedspectral efficiency. Services include wide-area wireless voice telephony, video calls,and broadband wireless data, all in a mobile environment. Additional features alsoinclude HSPA data transmission capabilities able to deliver speeds up to 14.4Mbit/son the downlink and 5.8Mbit/s on the uplink.Unlike IEEE 802.11 networks, 3G networks are wide area cellular telephonenetworks which evolved to incorporate high-speed internet access and videotelephony. IEEE 802.11 (common names Wi-Fi or WLAN) networks are short range,high-bandwidth networks primarily developed for data.Implementation and historyThe first pre-commercial 3G network was launched by NTT DoCoMo in Japanbranded FOMA, in May of 2001 on a pre-release of W-CDMA technology. The firstcommercial launch of 3G was also by NTT DoCoMo in Japan on October 1, 2001.The second network to go commercially live was by SK Telecom in South Korea onthe CDMA2000 1xEV-DO technology.The first European pre-commercial network was at the Isle of Man by ManxTelecom, the operator owned by British Telecom, and the first commercial network inEurope was opened for business by Telenor in December 2001 with no commercial 39
  40. 40. handsets and thus no paying customers. These were both on the W-CDMAtechnology.The first commercial United States 3G network was by Monet, on CDMA2000 1x EV-DO technology, but this network provider later shut down operations. The first UMTS3G network operator in the USA was Verizon.The "first pre-commercial demonstration network" in the southern hemisphere wasbuilt in Adelaide, South Australia by m.Net Corporation in February 2002 usingUMTS on 2100MHz. This was a demonstration network for the 2002 IT WorldCongress. The first "commercial" 3G network was launched by HutchisonTelecommunications branded as Three in April 2003. Australias largest and fastest3G UMTS/HSDPA network was launched by Telstra branded as "NextG(tm)" on the850MHz band in October 2006, intended as a replacement of their cdmaOnenetwork Australia wide.In December 2007, 190 3G networks were operating in 40 countries and 154HSDPA networks were operating in 71 countries, according to the Global mobileSuppliers Association. In Asia, Europe, Canada and the USA, telecommunicationcompanies use W-CDMA technology with the support of around 100 terminaldesigns to operate 3G mobile networks.In Europe, mass market commercial 3G services were introduced starting in March2003 by 3 (Part of Hutchison Whampoa) in the UK and Italy. The European UnionCouncil suggested that the 3G operators should cover 80% of the European nationalpopulations by the end of 2005.Roll-out of 3G networks was delayed in some countries by the enormous costs ofadditional spectrum licensing fees. (See Telecoms crash.) In many countries, 3Gnetworks do not use the same radio frequencies as 2G, so mobile operators mustbuild entirely new networks and license entirely new frequencies; an exception is theUnited States where carriers operate 3G service in the same frequencies as otherservices. The license fees in some European countries were particularly high,bolstered by government auctions of a limited number of licenses and sealed bidauctions, and initial excitement over 3Gs potential. Other delays were due to theexpenses of upgrading equipment for the new systems.By June 2007 the 200 millionth 3G subscriber had been connected. Out of 3 billionmobile phone subscriptions worldwide this is only 6.7%. In the countries where 3Gwas launched first - Japan and South Korea - over half of all subscribers use 3G. In 40
  41. 41. Europe the leading country is Italy with a third of its subscribers migrated to 3G.Other leading countries by 3G migration include UK, Austria, Australia andSingapore at the 20% migration level. A confusing statistic is counting CDMA 20001x RTT customers as if they were 3G customers. If using this oft-disputed definition,then the total 3G subscriber base would be 475 million at June 2007 and 15.8% of allsubscribers worldwide.Still several major countries such as Turkey, China etc have not awarded 3Glicenses and customers await 3G services. China has been delaying its decisions on3G for many years, partly hoping to have the Chinese 3G standard, TD-SCDMA, tomature for commercial production.The first African use of 3G technology was a 3G videocall made in Johannesburg onthe Vodacom network in November 2004. The first commercial launch of 3G in Africawas by EMTEL in Mauritius on the W-CDMA standard. In north African Morocco inlate March 2006, a 3G service was provided by the new company Wana.Rogers Wireless began implementing 3G HSDPA services in eastern Canada early2007 in the form of Rogers Vision; expansion into western Canada is expected soon.Phones and networks 3G technologies enable network operators to offer users a wider range of moreadvanced services while achieving greater network capacity through improvedspectral efficiency.UMTS terminals The technical complexities of a 3G phone or handset depends on its need toroam onto legacy 2G networks. In the first countries, Japan and South Korea, therewas no need to include roaming capabilities to older networks such as GSM, so 3Gphones were small and lightweight. In Europe and America, the manufacturers andnetwork operators wanted multi-mode 3G phones which would operate on 3G and2G networks (e.g., W-CDMA and GSM), which added to the complexity, size, weight, 41
  42. 42. and cost of the handset. As a result, early European W-CDMA phones weresignificantly larger and heavier than comparable Japanese W-CDMA phones.Japans Vodafone KK experienced a great deal of trouble with these differenceswhen its UK-based parent, Vodafone, insisted the Japanese subsidiary use standardVodafone handsets. Japanese customers who were accustomed to smaller handsetswere suddenly required to switch to European handsets that were much bulkier andconsidered unfashionable by Japanese consumers. During this conversion,Vodafone KK lost 6 customers for every 4 that migrated to 3G. Soon thereafter,Vodafone sold the subsidiary (now known as SoftBank Mobile).The general trend to smaller and smaller phones seems to have paused, perhapseven turned, with the capability of large-screen phones to provide more video,gaming and internet use on the 3G networks.Speed The ITU has not provided a clear definition of the speeds users can expectfrom 3G equipment or providers. Thus users sold 3G service may not be able topoint to a standard and say that the speeds it specifies are not being met. Whilestating in commentary that "it is expected that IMT-2000 will provide highertransmission rates: a minimum speed of 2Mbit/s for stationary or walking users, and348 <sic> kbit/s in a moving vehicle,"[1] the ITU does not actually clearly specifyminimum or average speeds or what modes of the interfaces qualify as 3G, sovarious speeds are sold as 3G intended to meet customers expectations ofbroadband speed. It is often suggested by industry sources that 3G can be expectedto provide 384 Kbps at or below pedestrian speeds, but only 128 Kbps in a movingcar[2]. While EDGE is part of the 3G standard, some phones report EDGE and 3Gnetwork availability as separate things.Network standardization The International Telecommunication Union (ITU) defined the demands for 3Gmobile networks with the IMT-2000 standard. An organization called 3rd GenerationPartnership Project (3GPP) has continued that work by defining a mobile system that 42
  43. 43. fulfills the IMT-2000 standard. This system is called Universal MobileTelecommunications System (UMTS).IMT-2000 standards and radio interfacesInternational Telecommunications Union (ITU): IMT-2000 consists of six radiointerfaces W-CDMA CDMA2000 TD-CDMA / TD-SCDMA UWC (often implemented with EDGE) DECT Mobile WiMAXAdvantages of a layered network architectureUnlike GSM, UMTS is based on layered services. At the top is the services layer,which provides fast deployment of services and centralized location. In the middle isthe control layer, which helps upgrading procedures and allows the capacity of thenetwork to be dynamically allocated. At the bottom is the connectivity layer whereany transmission technology can be used and the voice traffic will transfer over ATM/AAL2 or IP/RTP.3G evolution (pre-4G).The standardization of 3G evolution is working in both 3GPP and 3GPP2. Thecorresponding specifications of 3GPP and 3GPP2 evolutions are named as LTE andUMB, respectively. 3G evolution uses partly beyond 3G technologies to enhance theperformance and to make a smooth migration path.There are several different paths from 2G to 3G. In Europe the main path starts fromGSM when GPRS is added to a system. From this point it is possible to go to theUMTS system. In North America the system evolution will start from Time divisionmultiple access (TDMA), change to Enhanced Data Rates for GSM Evolution(EDGE) and then to UMTS. 43
  44. 44. In Japan, two 3G standards are used: W-CDMA used by NTT DoCoMo (FOMA,compatible with UMTS) and SoftBank Mobile (UMTS), and CDMA2000, used byKDDI. Transition to 3G was completed in Japan in 2006.Evolution from 2G to 3G2G networks were built mainly for voice data and slow transmission. Due to rapidchanges in user expectation, they do not meet todays wireless needs.Cellular mobile telecommunications networks are being upgraded to use 3Gtechnologies from 1999 to 2010. Japan was the first country to introduce 3Gnationally, and in Japan the transition to 3G was largely completed in 2006. Koreathen adopted 3G Networks soon after and the transition was made as early as 2004.From 2G to 2.5G (GPRS) "2.5G" (and even 2.75G) are technologies such as i-mode data services,camera phones, high-speed circuit-switched data (HSCSD) and General packetradio service (GPRS) were created to provide some functionality domains like 3Gnetworks, but without the full transition to 3G network. They were built to introducethe possibilities of wireless application technology to the end consumers, and soincrease demand for 3G services.When converting a GSM network to a UMTS network, the first new technology isGeneral Packet Radio Service (GPRS). It is the trigger to 3G services. The networkconnection is always on, so the subscriber is online all the time. From the operatorspoint of view, it is important that GPRS investments are re-used when going toUMTS. Also capitalizing on GPRS business experience is very important.From GPRS, operators could change the network directly to UMTS, or invest in anEDGE system. One advantage of EDGE over UMTS is that it requires no newlicenses. The frequencies are also re-used and no new antennas are needed.Migrating from GPRS to UMTSFrom GPRS network, the following network elements can be reused: Home location register (HLR) Visitor location register (VLR) Equipment identity register (EIR) 44
  45. 45. Mobile switching centre (MSC) (vendor dependent) Authentication centre (AUC) Serving GPRS Support Node (SGSN) (vendor dependent) Gateway GPRS Support Node (GGSN)From Global Service for Mobile (GSM) communication radio network, the followingelements cannot be reused Base station controller (BSC) Base transceiver station (BTS)They can remain in the network and be used in dual network operation where 2Gand 3G networks co-exist while network migration and new 3G terminals becomeavailable for use in the network.The UMTS network introduces new network elements that function as specified by3GPP: Node B (base station) Radio Network Controller (RNC) Media Gateway (MGW)The functionality of MSC and SGSN changes when going to UMTS. In a GSMsystem the MSC handles all the circuit switched operations like connecting A- and B-subscriber through the network. SGSN handles all the packet switched operationsand transfers all the data in the network. In UMTS the Media gateway (MGW) takecare of all data transfer in both circuit and packet switched networks. MSC andSGSN control MGW operations. The nodes are renamed to MSC-server and GSN-server.IssuesAlthough 3G was successfully introduced to users in Europe, Australia, Asia, SouthAmerica, North America and Africa, some issues are debated by 3G providers andusers: Expensive input fees for the 3G service licenses Numerous differences in the licensing terms Large amount of debt currently sustained by many telecommunicationcompanies, which makes it a challenge to build the necessary infrastructure for 3G Lack of member state support for financially troubled operators Expense of 3G phones 45
  46. 46. Lack of buy-in by 2G mobile users for the new 3G wireless services Lack of coverage, because it is still a new service High prices of 3G mobile services in some countries, including Internet access(see flat rate) Current lack of user need for 3G voice and data services in a hand-helddevice High power usage VoDVoD stands for Video on Demand. VoD permits a customer to browse an onlineprogramme or film catalogue, to watch trailers and to then select a selectedrecording for playback. The playout of the selected movie starts nearlyinstantaneously on the customers TV or PC.Technically, when the customer selects the movie, a point-to-point unicastconnection is set up between the customers decoder (SetTopBox or PC) and thedelivering streaming server. The signalling for the trick play functionality (pause,slow-motion, wind/rewind etc.) is assured by RTSP (Real Time Streaming Protocol).The most common codecs used for VoD are MPEG-2, MPEG-4 and VC-1.In an attempt to avoid content piracy, the VoD content is usually encrypted. Whilstencryption of satellite and cable TV broadcasts is an old practice, with IPTVtechnology it can effectively be thought of as a form of Digital Rights Management. Afilm that is chosen, for example, may be playable for 24 hours following payment,after which time it becomes unavailable.IPTV based Converged ServicesAnother advantage of an IP-based network is the opportunity for integration andconvergence. Converged services implies interaction of existing services in aseamless manner to create new value added services. One good example is On-Screen Caller ID, getting Caller ID on your TV and the ability to handle it (send it tovoice mail, etc). IP-based services will help to enable efforts to provide consumersanytime-anywhere access to content over their televisions, PCs and cell phones, and 46
  47. 47. to integrate services and content to tie them together. Within businesses andinstitutions, IPTV eliminates the need to run a parallel infrastructure to deliver liveand stored video services.LimitationsBecause IPTV requires real-time data transmission and uses the Internet Protocol, itis sensitive to packet loss and delays if the streamed data is unreliable. If the IPTVconnection is not fast enough, picture break-up or loss may occur. This problem hasproved particularly troublesome when attempting to stream IPTV across wirelesslinks. Improvements in wireless technology are now starting to provide equipment tosolve the problemMP-3MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a digital audioencoding format using a form of lossy data compression.It is a common audio format for consumer audio storage, as well as a de factostandard encoding for the transfer and playback of music on digital audio players.MP3 is an audio-specific format that was co-designed by several teams of engineersat Fraunhofer IIS in Erlangen, Germany, AT&T-Bell Labs in Murray Hill, NJ, USA,Thomson-Brandt, and CCETT. It was approved as an ISO/IEC standard in 1991.MP3s use of a lossy compression algorithm is designed to greatly reduce theamount of data required to represent the audio recording and still sound like a faithfulreproduction of the original uncompressed audio for most listeners, but is notconsidered high fidelity audio by most audiophiles. An MP3 file that is created usingthe mid-range bitrate setting of 128 kbit/s will result in a file that is typically about1/10th the size of the CD file created from the original audio source. An MP3 file canalso be constructed at higher or lower bitrates, with higher or lower resulting quality.The compression works by reducing accuracy of certain parts of sound that aredeemed beyond the auditory resolution ability of most people. This method iscommonly referred to as Perceptual Coding. [1] It internally provides arepresentation of sound within a short term time/frequency analysis window, by usingpsychoacoustic models to discard or reduce precision of components less audible to 47
  48. 48. human hearing, and recording the remaining information in an efficient manner. Thisis relatively similar to the principles used by JPEG, an image compression format.InternetFrom the first half of 1995 through the late 1990s, MP3 files began to spread on theInternet. MP3s popularity began to rise rapidly with the advent of Nullsofts audioplayer Winamp (released in 1997), and the Unix audio player mpg123. The smallsize of MP3 files has enabled widespread peer-to-peer file sharing of music rippedfrom compact discs, which would previously have been nearly impossible. The firstlarge peer-to-peer filesharing network, Napster, was released in 1999.The ease of creating and sharing MP3s resulted in widespread copyrightinfringement. Major record companies argue that this free sharing of music reducessales, and call it "music piracy". They reacted by pursuing lawsuits against Napster(which was eventually shut down) and eventually against individual users whoengaged in file sharing.Despite the popularity of MP3, online music retailers often use other proprietaryformats that are encrypted (known as Digital rights management) to prevent usersfrom using purchased music in ways not specifically authorized by the recordcompanies. The record companies argue that this is necessary to prevent the filesfrom being made available on peer-to-peer file sharing networks. However, this hasother side effects such as preventing users from playing back their purchased musicon different types of devices. The audio content of these files can be converted intoan unencrypted format, however, because often the user permissions include "burnto audio CD". And even when that option is not available, many sound cards allowthe user to record anything they play. Unauthorized MP3 filesharing continues onnext-generation peer-to-peer networks, though some authorized services, such aseMusic, and Amazon.com sell unrestricted music in the MP3 format.Encoding audioThe MPEG-1 standard does not include a precise specification for an MP3 encoder.Implementers of the standard were supposed to devise their own algorithms suitablefor removing parts of the information in the raw audio (or rather its MDCTrepresentation in the frequency domain). During encoding, 576 time domain samplesare taken and are transformed to 576 frequency domain samples. If there is a 48
  49. 49. transient, 192 samples are taken instead of 576. This is done to limit the temporalspread of quantization noise accompanying the transient.As a result, there are many different MP3 encoders available, each producing files ofdiffering quality. Comparisons are widely available, so it is easy for a prospectiveuser of an encoder to research the best choice. It must be kept in mind that anencoder that is proficient at encoding at higher bit rates (such as LAME) is notnecessarily as good at lower bit rates.Decoding audioDecoding, on the other hand, is carefully defined in the standard. Most decoders are"bitstream compliant", which means that the decompressed output - that theyproduce from a given MP3 file - will be the same (within a specified degree ofrounding tolerance) as the output specified mathematically in the ISO/IEC standarddocument. The MP3 file has a standard format, which is a frame that consists of 384,576, or 1152 samples (depends on MPEG version and layer), and all the frameshave associated header information (32 bits) and side information (9, 17, or 32bytes, depending on MPEG version and stereo/mono). The header and sideinformation help the decoder to decode the associated Huffman encoded datacorrectly.Therefore, comparison of decoders is usually based on how computationally efficientthey are (i.e., how much memory or CPU time they use in the decoding process).Audio qualityWhen performing lossy audio encoding, such as creating an MP3 file, there is atrade-off between the amount of space used and the sound quality of the result.Typically, the creator is allowed to set a bit rate, which specifies how many kilobitsthe file may use per second of audio, for example, when ripping a compact disc tothis format. The lower the bit rate used, the lower the audio quality will be, but thesmaller the file size. Likewise, the higher the bit rate used, the higher the quality, andtherefore, larger the resulting file will be.Files encoded with a lower bit rate will generally play back at a lower quality. Withtoo low a bit rate, "compression artifacts" (i.e., sounds that were not present in theoriginal recording) may be audible in the reproduction. Some audio is hard tocompress because of its randomness and sharp attacks. When this type of audio is 49
  50. 50. compressed, artifacts such as ringing or pre-echo are usually heard. A sample ofapplause compressed with a relatively low bitrate provides a good example ofcompression artifacts. Besides the bit rate of an encoded piece of audio, the quality of MP3 files alsodepends on the quality of the encoder itself, and the difficulty of the signal beingencoded. As the MP3 standard allows quite a bit of freedom with encodingalgorithms, different encoders may feature quite different quality, even whentargeting similar bit rates. As an example, in a public listening test featuring twodifferent MP3 encoders at about 128 kbit/s, one scored 3.66 on a 1–5 scale, whilethe other scored only 2.22. Quality is heavily dependent on the choice of encoder and encodingparameters. While quality around 128 kbit/s was somewhere between annoying andacceptable with older encoders, modern MP3 encoders can provide adequate qualityat those bit rates (January 2006). However, in 1998, MP3 at 128 kbit/s was onlyproviding quality equivalent to AAC-LC at 96 kbit/s and MP2 at 192 kbit/s.The transparency threshold of MP3 can be estimated to be at about 128 kbit/s withgood encoders on typical music as evidenced by its strong performance in the abovetest, however some particularly difficult material, or music encoded for the use ofpeople with more sensitive hearing can require 192 kbit/s or higher. As with all lossyformats, some samples cannot be encoded to be transparent for all users.The simplest type of MP3 file uses one bit rate for the entire file — this is known asConstant Bit Rate (CBR) encoding. Using a constant bit rate makes encodingsimpler and faster. However, it is also possible to create files where the bit ratechanges throughout the file. These are known as Variable Bit Rate (VBR) files. Theidea behind this is that, in any piece of audio, some parts will be much easier tocompress, such as silence or music containing only a few instruments, while otherswill be more difficult to compress. So, the overall quality of the file may be increasedby using a lower bit rate for the less complex passages and a higher one for themore complex parts. With some encoders, it is possible to specify a given quality,and the encoder will vary the bit rate accordingly. Users who know a particular"quality setting" that is transparent to their ears can use this value when encoding allof their music, and not need to worry about performing personal listening tests oneach piece of music to determine the correct settings. 50

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