Global Positioning System
The Global Positioning System Navstar GPS, is a satellite-based radionavigation system owned by the United States government and operated by the United States Air Force. It is a global navigation satellite system that provides geolocation and time information to a GPS receiver anywhere on or near the Earth where there is an unobstructed line of sight to four or more GPS satellites. Obstacles such as mountains and buildings block the weak GPS signals; the GPS does not require the user to transmit any data, it operates independently of any telephonic or internet reception, though these technologies can enhance the usefulness of the GPS positioning information. The GPS provides critical positioning capabilities to military and commercial users around the world; the United States government created the system, maintains it, makes it accessible to anyone with a GPS receiver. The GPS project was launched by the U. S. Department of Defense in 1973 for use by the United States military and became operational in 1995.
It was allowed for civilian use in the 1980s. Advances in technology and new demands on the existing system have now led to efforts to modernize the GPS and implement the next generation of GPS Block IIIA satellites and Next Generation Operational Control System. Announcements from Vice President Al Gore and the White House in 1998 initiated these changes. In 2000, the U. S. Congress authorized the modernization effort, GPS III. During the 1990s, GPS quality was degraded by the United States government in a program called "Selective Availability"; the GPS system is provided by the United States government, which can selectively deny access to the system, as happened to the Indian military in 1999 during the Kargil War, or degrade the service at any time. As a result, several countries have developed or are in the process of setting up other global or regional satellite navigation systems; the Russian Global Navigation Satellite System was developed contemporaneously with GPS, but suffered from incomplete coverage of the globe until the mid-2000s.
GLONASS can be added to GPS devices, making more satellites available and enabling positions to be fixed more and to within two meters. China's BeiDou Navigation Satellite System is due to achieve global reach in 2020. There are the European Union Galileo positioning system, India's NAVIC. Japan's Quasi-Zenith Satellite System is a GPS satellite-based augmentation system to enhance GPS's accuracy; when selective availability was lifted in 2000, GPS had about a five-meter accuracy. The latest stage of accuracy enhancement uses the L5 band and is now deployed. GPS receivers released in 2018 that use the L5 band can have much higher accuracy, pinpointing to within 30 centimetres or 11.8 inches. The GPS project was launched in the United States in 1973 to overcome the limitations of previous navigation systems, integrating ideas from several predecessors, including classified engineering design studies from the 1960s; the U. S. Department of Defense developed the system, which used 24 satellites, it was developed for use by the United States military and became operational in 1995.
Civilian use was allowed from the 1980s. Roger L. Easton of the Naval Research Laboratory, Ivan A. Getting of The Aerospace Corporation, Bradford Parkinson of the Applied Physics Laboratory are credited with inventing it; the work of Gladys West is credited as instrumental in the development of computational techniques for detecting satellite positions with the precision needed for GPS. The design of GPS is based on similar ground-based radio-navigation systems, such as LORAN and the Decca Navigator, developed in the early 1940s. Friedwardt Winterberg proposed a test of general relativity – detecting time slowing in a strong gravitational field using accurate atomic clocks placed in orbit inside artificial satellites. Special and general relativity predict that the clocks on the GPS satellites would be seen by the Earth's observers to run 38 microseconds faster per day than the clocks on the Earth; the GPS calculated positions would drift into error, accumulating to 10 kilometers per day. This was corrected for in the design of GPS.
Winterberg, Friedwardt. “Relativistische Zeitdilatation eines künstlichen Satelliten ” When the Soviet Union launched the first artificial satellite in 1957, two American physicists, William Guier and George Weiffenbach, at Johns Hopkins University's Applied Physics Laboratory decided to monitor its radio transmissions. Within hours they realized that, because of the Doppler effect, they could pinpoint where the satellite was along its orbit; the Director of the APL gave them access to their UNIVAC to do the heavy calculations required. Early the next year, Frank McClure, the deputy director of the APL, asked Guier and Weiffenbach to investigate the inverse problem—pinpointing the user's location, given that of the satellite; this led them and APL to develop the TRANSIT system. In 1959, ARPA played a role in TRANSIT. TRANSIT was first tested in 1960, it used a constellation of five satellites and could provide a navigational fix once per hour. In 1967, the U. S. Navy developed the Timation satellite, which proved the feasibility of placing accurate clocks in space, a technology required for GPS.
In the 1970s, the ground-based OMEGA navigation system, based on phase comparison of signal transmission from pairs of stations
IPhone 7 and iPhone 7 Plus are smartphones designed and marketed by Apple Inc. It is the tenth generation of the iPhone, they were announced on September 7, 2016, at the Bill Graham Civic Auditorium in San Francisco by Apple CEO Tim Cook, were released on September 16, 2016, succeeding the iPhone 6S and iPhone 6S Plus as the flagship devices in the iPhone series. Apple released the iPhone 7 and 7 Plus in numerous countries worldwide throughout September and October 2016, they were succeeded as flagship devices by the iPhone 8 and iPhone 8 Plus on September 22, 2017, the iPhone X on November 3, 2017. The iPhone 7's overall design is similar to the iPhone 6S, but introduces new color options and dust resistance, a new capacitive, static home button, removes the 3.5 mm headphone jack. The device's internal hardware received upgrades, including a heterogeneous quad-core system-on-chip with improved system and graphics performance, upgraded 12 megapixel rear-facing cameras with optical image stabilization on all models and an additional telephoto lens on the iPhone 7 Plus model to provide enhanced zoom capabilities.
Reception of the iPhone 7 was mixed. Although reviewers noted the improvements to the camera the dual rear camera on the Plus model, they stated that the iPhone 7 did not make significant changes to the display or build quality, where competing flagship smartphones surpassed the quality of the iPhone 7. Many reviews highlighted the controversial removal of the 3.5 mm headphone jack. Apple was mocked by critics for Phil Schiller's statement that such a drastic change required "courage"; the iPhone 7 has been the subject of several reported issues, most notably a hissing noise during heavy usage of the phones and significant differences in performance between device variants. Apple has not released sales numbers for iPhone 7, but multiple U. S. carriers reported. Subsequent reports at the end of 2016 stated that Apple had reduced production of the models due to "sluggish" sales and decreasing demand, though sales research after the first quarter of 2017 placed the devices as the best-selling smartphones in the world.
Prior to its official announcement, multiple aspects of the iPhone 7 were rumored. Apple's plans to remove the 3.5 mm headphone jack received significant media attention. Other rumors included a flush camera, stereo speakers, a 256 gigabyte storage option, a larger 3,100 mAh battery. On August 29, 2016, invitations to a press event at the Bill Graham Civic Auditorium in San Francisco, California on September 7, 2016 were sent out to members of the media, prompting immediate speculation of the iPhone 7's upcoming announcement; the iPhone 7 was announced at that event, with pre-orders beginning September 9, general availability on September 16. The iPhone 7 launched in 30 new countries in September, with further international rollouts throughout October and November 2016. Indonesia was the last country to release the iPhone 7 and 7 Plus, with availability starting on March 31, 2017, following Apple's research and development investment in the country. On March 21, 2017, Apple announced an iPhone 7 with a red color finish, as part of its partnership with Product Red to highlight its AIDS fundraising campaign.
It launched on March 24, 2017, but it was discontinued after the announcement of the iPhone 8, iPhone 8 Plus and iPhone X in September 2017. In September 2017, Apple announced the iPhone 8 and iPhone 8 Plus as direct successors to the iPhone 7 and 7 Plus, alongside the iPhone X; the iPhone 7's exterior is similar in shape and volume to the iPhone 6 and iPhone 6S. Alongside the existing silver and rose gold colors, the device is offered in new colors of matte black, glossy "jet black", for a limited time, red; the "jet black" color is high-gloss black finish. It is created through a multi-step process, beginning with an anodization phase to make the surface of the casing a porous aluminum oxide, using a machine to sweep the casing through a powdered compound, absorbed by aluminum oxide; the process is concluded with an "ultrafine particle bath" for additional finishing. The warranty does not cover any water damage to the phone.iPhone 7's home button uses a capacitive mechanism for input rather than a physical push-button, as on previous models, meaning direct skin contact is required to operate the device.
Physical feedback is provided via a Taptic Engine vibrator, the button is pressure-sensitive. IPhone 7 retains the 3D Touch display system introduced on the iPhone 6S, providing pressure-sensitive touchscreen input; the iPhone 7 does not feature a 3.5 mm headphone jack. A Lightning-to-3.5-mm-connector adapter, as well as in-ear headphones that use the Lightning connector, were bundled with the device, the adapter is sold separately as an accessory. The adapter is compatible with other iPhone, iPad, iPod Touch devices running iOS 10 and newer.iPhone 7 uses the Apple A10 Fusion 64-bit system-on-chip, which consists of two low-power cores and two high-power cores. The A10 chip features a hexa-core graphics chip capable of "console-level gaming"; as with
GLONASS, or "Global Navigation Satellite System", is a space-based satellite navigation system operating as part of a radionavigation-satellite service. It provides an alternative to GPS and is the second navigational system in operation with global coverage and of comparable precision. Manufacturers of GPS navigation devices say that adding GLONASS made more satellites available to them, meaning positions can be fixed more and especially in built-up areas where buildings may obscure the view to some GPS satellites. GLONASS supplementation of GPS systems improves positioning in high latitudes. Development of GLONASS began in the Soviet Union in 1976. Beginning on 12 October 1982, numerous rocket launches added satellites to the system, until the completion of the constellation in 1995. After a decline in capacity during the late 1990s, in 2001, under Vladimir Putin's presidency, the restoration of the system was made a top government priority and funding increased substantially. GLONASS is the most expensive program of the Russian Federal Space Agency, consuming a third of its budget in 2010.
By 2010 GLONASS had achieved 100% coverage of Russia's territory and in October 2011 the full orbital constellation of 24 satellites was restored, enabling full global coverage. The GLONASS satellites' designs have undergone several upgrades, with the latest version, GLONASS-K2, scheduled to enter service in 2019. An announcement predicts the deployment of a group of communications and navigational satellites by 2040; the task includes the delivery to the Moon of a series of spacecraft for orbital research and the establishment of a lunar communications and positioning system. GLONASS is a global satellite navigation system, providing real time position and velocity determination for military and civilian users; the satellites are located in middle circular orbit at 19,100 kilometres altitude with a 64.8 degree inclination and a period of 11 hours and 15 minutes. GLONASS's orbit makes it suited for usage in high latitudes, where getting a GPS signal can be problematic; the constellation operates with eight evenly spaced satellites on each.
A operational constellation with global coverage consists of 24 satellites, while 18 satellites are necessary for covering the territory of Russia. To get a position fix the receiver must be in the range of at least four satellites. GLONASS satellites transmit two types of signal: open standard-precision signal L1OF/L2OF, obfuscated high-precision signal L1SF/L2SF; the signals use similar DSSS binary phase-shift keying modulation as in GPS signals. All GLONASS satellites transmit the same code as their standard-precision signal; the center frequency is 1602 MHz + n × 0.5625 MHz, where n is a satellite's frequency channel number. Signals are transmitted in a 38° cone, using right-hand circular polarization, at an EIRP between 25 and 27 dBW. Note that the 24-satellite constellation is accommodated with only 15 channels by using identical frequency channels to support antipodal satellite pairs, as these satellites are never both in view of an earth-based user at the same time; the L2 band signals use the same FDMA as the L1 band signals, but transmit straddling 1246 MHz with the center frequency 1246 MHz + n×0.4375 MHz, where n spans the same range as for L1.
In the original GLONASS design, only obfuscated high-precision signal was broadcast in the L2 band, but starting with GLONASS-M, an additional civil reference signal L2OF is broadcast with an identical standard-precision code to the L1OF signal. The open standard-precision signal is generated with modulo-2 addition of 511 kbit/s pseudo-random ranging code, 50 bit/s navigation message, an auxiliary 100 Hz meander sequence, all generated using a single time/frequency oscillator; the pseudo-random code is generated with a 9-stage shift register operating with a period of 1 ms. The navigational message is modulated at 50 bits per second; the superframe of the open signal is 7500 bits long and consists of 5 frames of 30 seconds, taking 150 seconds to transmit the continuous message. Each frame is 1500 bits long and consists of 15 strings of 100 bits, with 85 bits for data and check-sum bits, 15 bits for time mark. Strings 1-4 provide immediate data for the transmitting satellite, are repeated every frame.
Strings 5-15 provide non-immediate data for each satellite in the constellation, with frames I-IV each describing five satellites, frame V describing remaining four satellites. The ephemerides are updated every 30 minutes using data from the Ground Control segment; the almanac is updated daily. The more accurate high-precision signal is available for authorized users, such as the Russian military, yet unlike the US P code, modulated by an encrypting W code, the GLONASS restricted-use codes are broadcast in the clear using only security through obscurity; the details of the high-precision signal have not been disclosed. The modulation
Wi-Fi is technology for radio wireless local area networking of devices based on the IEEE 802.11 standards. Wi‑Fi is a trademark of the Wi-Fi Alliance, which restricts the use of the term Wi-Fi Certified to products that complete after many years of testing the 802.11 committee interoperability certification testing. Devices that can use Wi-Fi technologies include, among others and laptops, video game consoles and tablets, smart TVs, digital audio players, digital cameras and drones. Wi-Fi compatible devices can connect to the Internet via a wireless access point; such an access point has a range of about 20 meters indoors and a greater range outdoors. Hotspot coverage can be as small as a single room with walls that block radio waves, or as large as many square kilometres achieved by using multiple overlapping access points. Different versions of Wi-Fi exist, with radio bands and speeds. Wi-Fi most uses the 2.4 gigahertz UHF and 5 gigahertz SHF ISM radio bands. Each channel can be time-shared by multiple networks.
These wavelengths work best for line-of-sight. Many common materials absorb or reflect them, which further restricts range, but can tend to help minimise interference between different networks in crowded environments. At close range, some versions of Wi-Fi, running on suitable hardware, can achieve speeds of over 1 Gbit/s. Anyone within range with a wireless network interface controller can attempt to access a network. Wi-Fi Protected Access is a family of technologies created to protect information moving across Wi-Fi networks and includes solutions for personal and enterprise networks. Security features of WPA have included stronger protections and new security practices as the security landscape has changed over time. In 1971, ALOHAnet connected the Hawaiian Islands with a UHF wireless packet network. ALOHAnet and the ALOHA protocol were early forerunners to Ethernet, the IEEE 802.11 protocols, respectively. A 1985 ruling by the U. S. Federal Communications Commission released the ISM band for unlicensed use.
These frequency bands are the same ones used by equipment such as microwave ovens and are subject to interference. In 1991, NCR Corporation with AT&T Corporation invented the precursor to 802.11, intended for use in cashier systems, under the name WaveLAN. The Australian radio-astronomer Dr John O'Sullivan with his colleagues Terence Percival, Graham Daniels, Diet Ostry, John Deane developed a key patent used in Wi-Fi as a by-product of a Commonwealth Scientific and Industrial Research Organisation research project, "a failed experiment to detect exploding mini black holes the size of an atomic particle". Dr O'Sullivan and his colleagues are credited with inventing Wi-Fi. In 1992 and 1996, CSIRO obtained patents for a method used in Wi-Fi to "unsmear" the signal; the first version of the 802.11 protocol was released in 1997, provided up to 2 Mbit/s link speeds. This was updated in 1999 with 802.11b to permit 11 Mbit/s link speeds, this proved to be popular. In 1999, the Wi-Fi Alliance formed as a trade association to hold the Wi-Fi trademark under which most products are sold.
Wi-Fi uses a large number of patents held by many different organizations. In April 2009, 14 technology companies agreed to pay CSIRO $1 billion for infringements on CSIRO patents; this led to Australia labeling Wi-Fi as an Australian invention, though this has been the subject of some controversy. CSIRO won a further $220 million settlement for Wi-Fi patent-infringements in 2012 with global firms in the United States required to pay the CSIRO licensing rights estimated to be worth an additional $1 billion in royalties. In 2016, the wireless local area network Test Bed was chosen as Australia's contribution to the exhibition A History of the World in 100 Objects held in the National Museum of Australia; the name Wi-Fi, commercially used at least as early as August 1999, was coined by the brand-consulting firm Interbrand. The Wi-Fi Alliance had hired Interbrand to create a name, "a little catchier than'IEEE 802.11b Direct Sequence'." Phil Belanger, a founding member of the Wi-Fi Alliance who presided over the selection of the name "Wi-Fi", has stated that Interbrand invented Wi-Fi as a pun on the word hi-fi, a term for high-quality audio technology.
Interbrand created the Wi-Fi logo. The yin-yang Wi-Fi logo indicates the certification of a product for interoperability; the Wi-Fi Alliance used the advertising slogan "The Standard for Wireless Fidelity" for a short time after the brand name was created. While inspired by the term hi-fi, the name was never "Wireless Fidelity"; the Wi-Fi Alliance was called the "Wireless Fidelity Alliance Inc" in some publications. Non-Wi-Fi technologies intended for fixed points, such as Motorola Canopy, are described as fixed wireless. Alternative wireless technologies include mobile phone standards, such as 2G, 3G, 4G, LTE; the name is sometimes written as WiFi, Wifi, or wifi, but these are not approved by the Wi-Fi Alliance. IEEE is a separate, but related organization and their website has stated "WiFi is a short name for Wireless Fidelity". To connect to a Wi-Fi LAN, a computer has to be equipped with a wireless network interface controller; the combination of computer and interface controllers is called a station.
A service set is the set of all the devices associated with a particular Wi-Fi network. The service set can be local, extended or mesh; each service set has an associated identifier, the 32-byte Service Set Identifier, which identifies the partic
In digital imaging, a pixel, pel, or picture element is a physical point in a raster image, or the smallest addressable element in an all points addressable display device. Each pixel is a sample of an original image; the intensity of each pixel is variable. In color imaging systems, a color is represented by three or four component intensities such as red and blue, or cyan, magenta and black. In some contexts, pixel refers to a single scalar element of a multi-component representation, while in yet other contexts it may refer to the set of component intensities for a spatial position; the word pixel is a portmanteau of el. The word "pixel" was first published in 1965 by Frederic C. Billingsley of JPL, to describe the picture elements of video images from space probes to the Moon and Mars. Billingsley had learned the word from Keith E. McFarland, at the Link Division of General Precision in Palo Alto, who in turn said he did not know where it originated. McFarland said it was "in use at the time".
The word is a combination of pix, for picture, element. The word pix appeared in Variety magazine headlines in 1932, as an abbreviation for the word pictures, in reference to movies. By 1938, "pix" was being used in reference to still pictures by photojournalists; the concept of a "picture element" dates to the earliest days of television, for example as "Bildpunkt" in the 1888 German patent of Paul Nipkow. According to various etymologies, the earliest publication of the term picture element itself was in Wireless World magazine in 1927, though it had been used earlier in various U. S. patents filed as early as 1911. Some authors explain pixel as picture cell, as early as 1972. In graphics and in image and video processing, pel is used instead of pixel. For example, IBM used it in their Technical Reference for the original PC. Pixels, abbreviated as "px", are a unit of measurement used in graphic and web design, equivalent to 1⁄96 inch; this measurement is used to make sure a given element will display as the same size no matter what screen resolution views it.
Pixilation, spelled with a second i, is an unrelated filmmaking technique that dates to the beginnings of cinema, in which live actors are posed frame by frame and photographed to create stop-motion animation. An archaic British word meaning "possession by spirits", the term has been used to describe the animation process since the early 1950s. A pixel is thought of as the smallest single component of a digital image. However, the definition is context-sensitive. For example, there can be "printed pixels" in a page, or pixels carried by electronic signals, or represented by digital values, or pixels on a display device, or pixels in a digital camera; this list is not exhaustive and, depending on context, synonyms include pel, byte, bit and spot. Pixels can be used as a unit of measure such as: 2400 pixels per inch, 640 pixels per line, or spaced 10 pixels apart; the measures dots per inch and pixels per inch are sometimes used interchangeably, but have distinct meanings for printer devices, where dpi is a measure of the printer's density of dot placement.
For example, a high-quality photographic image may be printed with 600 ppi on a 1200 dpi inkjet printer. Higher dpi numbers, such as the 4800 dpi quoted by printer manufacturers since 2002, do not mean much in terms of achievable resolution; the more pixels used to represent an image, the closer the result can resemble the original. The number of pixels in an image is sometimes called the resolution, though resolution has a more specific definition. Pixel counts can be expressed as a single number, as in a "three-megapixel" digital camera, which has a nominal three million pixels, or as a pair of numbers, as in a "640 by 480 display", which has 640 pixels from side to side and 480 from top to bottom, therefore has a total number of 640×480 = 307,200 pixels or 0.3 megapixels. The pixels, or color samples, that form a digitized image may or may not be in one-to-one correspondence with screen pixels, depending on how a computer displays an image. In computing, an image composed of pixels is known as a raster image.
The word raster originates from television scanning patterns, has been used to describe similar halftone printing and storage techniques. For convenience, pixels are arranged in a regular two-dimensional grid. By using this arrangement, many common operations can be implemented by uniformly applying the same operation to each pixel independently. Other arrangements of pixels are possible, with some sampling patterns changing the shape of each pixel across the image. For this reason, care must be taken when acquiring an image on one device and displaying it on another, or when converting image data from one pixel format to another. For example: LCD screens use a staggered grid, where the red and blue components are sampled at different locations. Subpixel rendering is a technology which takes advantage of these differences to improve the rendering of text on LCD screens; the vast
The Universal Mobile Telecommunications System is a third generation mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP, UMTS is a component of the International Telecommunications Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing cdmaOne technology. UMTS uses wideband code division multiple access radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators. UMTS specifies a complete network system, which includes the radio access network, the core network and the authentication of users via SIM cards; the technology described in UMTS is sometimes referred to as Freedom of Mobile Multimedia Access or 3GSM. Unlike EDGE and CDMA2000, UMTS requires new base stations and new frequency allocations. UMTS supports maximum theoretical data transfer rates of 42 Mbit/s when Evolved HSPA is implemented in the network. Users in deployed networks can expect a transfer rate of up to 384 kbit/s for Release'99 handsets, 7.2 Mbit/s for High-Speed Downlink Packet Access handsets in the downlink connection.
These speeds are faster than the 9.6 kbit/s of a single GSM error-corrected circuit switched data channel, multiple 9.6 kbit/s channels in High-Speed Circuit-Switched Data and 14.4 kbit/s for CDMAOne channels. Since 2006, UMTS networks in many countries have been or are in the process of being upgraded with High-Speed Downlink Packet Access, sometimes known as 3.5G. HSDPA enables downlink transfer speeds of up to 21 Mbit/s. Work is progressing on improving the uplink transfer speed with the High-Speed Uplink Packet Access. Longer term, the 3GPP Long Term Evolution project plans to move UMTS to 4G speeds of 100 Mbit/s down and 50 Mbit/s up, using a next generation air interface technology based upon orthogonal frequency-division multiplexing; the first national consumer UMTS networks launched in 2002 with a heavy emphasis on telco-provided mobile applications such as mobile TV and video calling. The high data speeds of UMTS are now most utilised for Internet access: experience in Japan and elsewhere has shown that user demand for video calls is not high, telco-provided audio/video content has declined in popularity in favour of high-speed access to the World Wide Web—either directly on a handset or connected to a computer via Wi-Fi, Bluetooth or USB.
UMTS combines three different terrestrial air interfaces, GSM's Mobile Application Part core, the GSM family of speech codecs. The air interfaces are called UMTS Terrestrial Radio Access. All air interface options are part of ITU's IMT-2000. In the most popular variant for cellular mobile telephones, W-CDMA is used, it is called "Uu interface", as it links User Equipment to the UMTS Terrestrial Radio Access Network Please note that the terms W-CDMA, TD-CDMA and TD-SCDMA are misleading. While they suggest covering just a channel access method, they are the common names for the whole air interface standards. W-CDMA or WCDMA, along with UMTS-FDD, UTRA-FDD, or IMT-2000 CDMA Direct Spread is an air interface standard found in 3G mobile telecommunications networks, it supports conventional cellular voice, text and MMS services, but can carry data at high speeds, allowing mobile operators to deliver higher bandwidth applications including streaming and broadband Internet access. W-CDMA uses the DS-CDMA channel access method with a pair of 5 MHz wide channels.
In contrast, the competing CDMA2000 system uses one or more available 1.25 MHz channels for each direction of communication. W-CDMA systems are criticized for their large spectrum usage, which delayed deployment in countries that acted slowly in allocating new frequencies for 3G services; the specific frequency bands defined by the UMTS standard are 1885–2025 MHz for the mobile-to-base and 2110–2200 MHz for the base-to-mobile. In the US, 1710–1755 MHz and 2110–2155 MHz are used instead, as the 1900 MHz band was used. While UMTS2100 is the most deployed UMTS band, some countries' UMTS operators use the 850 MHz and/or 1900 MHz bands, notably in the US by AT&T Mobility, New Zealand by Telecom New Zealand on the XT Mobile Network and in Australia by Telstra on the Next G network; some carriers such as T-Mobile use band numbers to identify the UMTS frequencies. For example, Band I, Band IV, Band V. UMTS-FDD is an acronym for Universal Mobile Telecommunications System - frequency-division duplexing and a 3GPP standardized version of UMTS networks that makes use of frequency-division duplexing for duplexing over an UMTS Terrestrial Radio Access air interface.
W-CDMA is the basis of Japan's NTT DoCoMo's FOMA service and the most-commonly used member of the Universal Mobile Telecommunications System family and sometimes used as a synonym for UMTS. It uses the DS-CDMA channel access method and the FDD duplexing method to achieve higher speeds and support more users compared to most used time division multiple access and time division duplex schemes. While not an evolutionary upgrade on the airside, it uses the same core network as the 2G GSM networks deployed worldwide, allowing dual mode mobile operation al
The iTunes Store is a software-based online digital media store operated by Apple Inc. that opened on April 28, 2003, as a result of Steve Jobs' push to open a digital marketplace for music. As of January 2017, iTunes offered over 35-40 million songs, 2.2 million apps, 25,000 TV shows, 65,000 films. When it opened, it was the only legal digital catalog of music to offer songs from all five major record labels; as of June 2013, iTunes Store possessed 575 million active user accounts, served over 315 million mobile devices, including Apple Watches, iPods, iPhones, Apple TV and iPads. Steve Jobs saw the opportunity to open a digital marketplace for music due to the rising popularity of downloadable tracks. In 2002, Jobs made an agreement with the five major record labels to offer their content through iTunes. ITunes Store was introduced by Jobs at the company's Worldwide Developers Conference in April 2003, it was available on Mac computers and the iPod, was expanded to Microsoft Windows in October 2003.
In April 2008, the iTunes Store was the largest music vendor in the United States, in February 2010, it was the largest music vendor in the world. ITunes Store's revenues in the first quarter of 2011 totaled nearly US$1.4 billion. By May 28, 2014, the store had sold 35 billion songs worldwide. In 2016, it was reported, it was reported that iTunes-style digital download sales had dropped 24% as streaming sales continued to increase. In April 2018, the iTunes app was added to the Microsoft Windows 10 app store. Beginning in the spring of 2019, the iTunes app became available on Samsung Smart TVs. Following the introduction of iTunes Store, individual songs were all sold for the same price, though Apple introduced multiple prices in 2007. Music in the store is in the Advanced Audio Coding format, the MPEG-4-specified successor to MP3. Songs were only available with DRM and were encoded at 128 kbit/s. At the January 2009 Macworld Expo, Apple announced that all iTunes music would be made available without DRM, encoded at the higher-quality rate of 256 kbit/s.
This model, known as "iTunes Plus", had been available only for music from EMI and some independent labels. Users can sample songs by listening to previews, ninety seconds in length, or thirty seconds for short tracks. In addition, iTunes Store offers apps, which are applications used for various purposes that are compatible with the iPod Touch, iPhone, iPad, although some apps are for the iPhone or iPad only; some Apps cost money and some are free. Developers can decide which prices they want to charge for apps, from a pre-set list of pricing tiers, from free to several hundred dollars; when someone downloads an App, 70 percent of the purchase goes to the developer, 30 percent goes to Apple. At the Macworld 2008 keynote, Steve Jobs, Apple's CEO at the time, announced iTunes movie rentals. Movies are available for rent in iTunes Store on the same day they are released on DVD, though iTunes Store offers for rental some movies that are still in theaters. Movie rentals are only viewable for 48 hours after users begin viewing them.
ITunes Store offers one low-priced movie rental a week: in the United States, this rental costs 99 cents. Movie rentals are not yet available in all countries but it is available in the United States, the United Kingdom, Canada and New Zealand. There is a weekly promotion in which one to three songs are available to download for free to logged-in users. Free downloads are available on Tuesdays, remain free until the following Tuesday, when the store gets refreshed with new content; some artists choose to have select songs available for no charge. This is not available at all iTunes Stores; some iTunes television programs have begun the same technique to encourage brand loyalty. In fact, iTunes Store has a "Free TV Episodes" page where free episodes are organized by length, either as "featurettes" or full length episodes. Free content can vary from a preview of a show to bonus content to pilot episodes and entire seasons of TV shows; some networks, such as ABC and NBC, have their own pages of "Free Season Premieres".
While the US iTunes Store has offered as many as three free songs each week in recent years, the store has instead replaced the three aforementioned categories with a unified "Single of the Week" banner, with the week's single being from a new up and coming artist. In 2015, Apple discontinued the "Single of the Week" program. A song costs 99¢. By default, songs that are more than 10 minutes are considered "Album Only". For special offers, song prices can be free. By default, music albums cost $9.99 or the price of all the songs combined if it is less than $9.99. However, the music album's distributor can set a higher price for the album, which happens on popular music albums. For special offers, prices of music albums can be dropped to $5.99, $6.99, or $7.99. On June 30, 2015 Apple launched Apple Music as a subscription service available in 110 countries. New subscribers are offered a three-month free trial with ongoing subscriptions priced from $9.99/month in the US and £9.99 in the UK. By default, H