Tuesday, July 30, 2013
Google launches Views hub to showcase Photo Spheres and panoramas in Google Maps
As slick as Android's Photo Spheres can be, they're typically hard to find unless someone posts them for you. Google is making that discovery almost trivial by launching Views, its new Google Maps section for Photo Spheres and panoramas. The page both streamlines importing photos from Google+ and simplifies tracking them down by their author, location or popularity. Google also includes its Street View galleries, giving explorers fast access to professional tours alongside the usual amateur photography. Not many of us can contribute to Views when Photo Sphere only works with a few of the latest Android devices,
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Google launches Views hub to showcase Photo Spheres and panoramas in Google Maps
Thursday, July 25, 2013
Sony Xperia se actualizarán a Android 4.3 Jelly Bean?
Si bien el proceso de actualización a Android 4.1 de sus Xperia 2012 no fue demasiado bueno, parece que las cosas han cambiado y que Sony se ha puesto a trabajar para mejorar en este aspecto. La actualización a Jelly Bean 4.2 para el Xperia Z y Xperia ZL ya han comenzado hace rato y a partir de principios de agosto comenzarán a recibirla el Xperia ZR y la Xperia Tablet Z.Sin embargo, en el día de ayer Google presentó Android 4.3 y Sony rápidamente ha llevado tranquilidad a sus usuarios anunciando qué dispositivos recibirán esta actualización. Los afortunados en primera instancia serán:- Xperia Z
- Xperia ZL
- Xperia ZR
- Xperia Tablet Z
- Xperia SP
- Xperia Z Ultra
Además, hay algunos dispositivos que darán el salto directamente de Android 4.1 a 4.3 aunque todavía no se han dado detalles acerca de qué dispositivos serán. La firma ha prometido dar más información sobre las fechas de actualización en las próximas semanas así que estaremos al atentos para mantenrlos al tanto.Ojalá Sony cumpla con su promesa y que las operadoras no se retrasen en lanzar las actualizaciones como suele suceder. Fabricantes y operadoras deberían mejorar en este aspecto para poder ofrecer a los usuarios las versiones de Android más recientes más rápidamente. Igualmente creo que Sony va por buen camino así que bien por ellos!
Quoting : ¿Qué Sony Xperia se actualizarán a Android 4.3 Jelly Bean? - Android Zone
producing 3GB mobile RAM; in time for Galaxy Note 3 and LG G2?
Samsung on Wednesday announced that it has started mass-producing 3GB LPDDR3 memory for smartphones, revealing that the first handsets to pack 3GB of RAM should ship in the second half of the year.
Previous reports did say that the company’s next flagship smartphone – the Galaxy Note 3 – will come with 3GB of memory under the hood, and Samsung’s announcement arrived just in time to further fuel such speculation. Not to mention that the LG G2 is also expected to have 3GB of RAM on board.
After all, we can safely assume that only high-end handsets will offer such hardware, with Galaxy Note 3 and the LG G2 being prime candidates to use the new low-powered RAM.
In addition to being power-efficient, the new RAM modules are faster, offer “full” LTE-A support and will let device makers create even slimmer devices and utilize saved space for bigger batteries or other components:
The Samsung 3GB LPDDR3 mobile DRAM uses six of the industry's smallest 20-nanometer (nm) class* four gigabit (Gb) LPDDR3 chips, in a symmetrical structure of two sets of three chips stacked in a single package only 0.8 millimeters high. With a full line-up of package dimensions, Samsung's new ultra-slim memory solutions will enable thinner smartphone designs and allow for additional battery space, while offering a data transfer speed of up to 2,133 megabits per second (Mbps) per pin.
The next step for the company is developing a 3GB module based on four 6Gb LPDDR3 DRAM chips to further improve RAM performance.
While we can’t confirm at this point whether the Galaxy Note 3 and LG G2 will indeed use the new 3GB RAM modules from Samsung, the company does say in its press release that the “initial adoption will expand to most high-end smartphones worldwide next year,” suggesting it will provide such components to a variety of mobile device makers.
Quoting : Samsung starts producing 3GB mobile RAM; in time for Galaxy Note 3 and LG G2?
Taiwan's MediaTek to launch a 'true' 8-core chip later this year | PCWorld
Smartphone and tablet chip vendor MediaTek has unveiled an octo-core processor it says can run all eight cores simultaneously when active.
The Taiwan-based company plans to launch the chip in the fourth quarter, MediaTek spokeswoman Sharon Lo said Thursday.
MediaTek said the product is a “true octo-core solution,” whereas other existing octo-core processors can only switch between using four cores at a time, the company claimed.
For example, Samsung’s previous octo-core chip, the Exynos 5410, is essentially two quad-core chips packed together and was used in some versions of its Galaxy S4 smartphone. One set of quad-core chips is designed for high-performance tasks such as gaming or video playback, while the other is made to handle less intensive processes like emailing or texting. But only four of the cores can be active at one time.MediaTek, however, said that its own octo-core chip can run each core independently, helping it to reduce excessive battery use while improving performance. With the chip, a device can allocations applications such as Internet browser tabs to individual cores, offering better stability in processing.
The Taiwanese vendor is aiming to grab more mobile processor market share, and has been releasing more quad-core chips recently. An octo-core chip could help the company find a place for its chips in higher-end smartphones and tablets.
The flexibility of MediaTek’s octo-core chip might soon be matched by Samsung, which on Tuesday unveiled a new octo-core chip, the Exynos 5420, which will go into mass production this August. It offers enhanced performance over the Exynos 5410, with higher clock speeds and a better GPU.
Samsung didn’t say whether all eight cores of the Exynos 5420 can operate at the same time, but it’s possible the new chip has been built with the capability, said Roger Sheng, an analyst with research firm Gartner.
Quoting : Taiwan's MediaTek to launch a 'true' 8-core chip later this year | PCWorld
Tuesday, July 23, 2013
Samsung Brings Enhanced Mobile Graphics Performance Capabilities to New Exynos 5 Octa Processor | SAMSUNG TOMORROW Global
Samsung Electronics introduced the latest addition to the Exynos product family with top level of graphic performance driven by a six-core ARM® Mali™-T628 GPU processor for the first time in the industry. With mobile use case scenarios becoming increasingly complex, Samsung’s newest eight-core ARM Cortex™ application processor gives designers a powerful, energy efficient tool to build multifaceted user interface capabilities directly into the system architecture. Samsung will demonstrate the new Exynos 5 family at SIGGRAPH 2013 in the ARM booth, #357, Exhibit Hall C at the Anaheim Convention Center. - See more at: http://global.samsungtomorrow.com/?p=26025#sthash.lFQ7l12w.dpuf
Samsung’s new Exynos 5 Octa, Exynos 5420, based on ARM Mali™-T628 MP6 cores, boosts 3D graphic processing capabilities that are over two times greater than the Exynos 5 Octa predecessor. The newest member of the Exynos family is able to perform General-Purpose computing on Graphics Processing Units (GPGPU) accelerating complex and computationally intensive algorithms or operations, traditionally processed by the CPU. This product also supports OpenGL® ES 3.0 and Full Profile Open CL 1.1, which enables the horsepower needed in multi-layer rendering of high-end, complex gaming scenarios, post-processing and sharing of photos and video, as well as general high-function multi-tasking operations. - See more at: http://global.samsungtomorrow.com/?p=26025#sthash.lFQ7l12w.dpuf
source : Samsung Brings Enhanced Mobile Graphics Performance Capabilities to New Exynos 5 Octa Processor | SAMSUNG TOMORROW Global
Monday, July 22, 2013
LG August 7 event invitation confirms G2 unveiling - SlashGear
LG sent out invitations for its August 7 event earlier this month, hinting that it would be unveiling the LG G2 with a couple of careful letters and numbers in the image. Now it has fired of another invitation, this time leaving no doubt that it will be showing off the handset next month, as well as providing the first official look at the smartphone.
The invitation states that participants will get to “experience” the LG G2, removing the doubt no one had at this point that the handset will be making its appearance on August 7. This comes shortly after the company confirmed the name of the device in a separate announcement, dropping the “Optimus” tag as many leaks have suggested.The LG G2 will be kicking off a line of premium handsets that all fall under the “G” brand, according to that announcement, with a separate line of handsets falling under the “Vu:” brand. While the event invitation doesn’t give a particularly detailed look at the device, it does confirm the existence of the buttons on the back of the handset, which will serve as power and volume rockers.The unconventional button layout, which we first heard about back in April, is said to be the result of how thin the handset is, with there being no room on the edges for typical button placement. Some suggest the buttons will serve more than simple power and volume control, but that is yet to be seen.According to other leaks, the LG G2 will feature a 5.2-inch display, and will run a Qualcomm Snapdragon 800 2.2GHz processor along with 2GB of RAM. There’s said to be a 13-megapixel rear camera, with the software being Android 4.2.2 Jelly Bean. You can find out more about what we’ve already heard in the timeline below, and of course we’ll be here with all the details on August 7.
Source : LG August 7 event invitation confirms G2 unveiling - SlashGear
Saturday, July 20, 2013
Friday, July 19, 2013
Ya es oficial, el Moto X de Motorola será presentado el 1 de Agosto en Nueva York
Después de innumerables rumores y filtraciones lo que tenemos claro es que el nuevo Smartphone de Motorola, el Moto X, será presentado el día 1 de Agosto en Nueva York. Asi nos lo hacen saber los chicos de Google mediante una invitación al evento de prensa que se celebrará en dicha ciudad.
Sobre las especificaciones no se dice nada aún (salvo parte de la carcasa trasera que se ve en la imagen) por lo que deberemos de fiarnos de lo que nos dicen los últimos rumores, que el Moto X posee una pantalla de 720p y un procesador Qualcomm Snapdragon S4 Pro a 1.7 GHz, 2 GB de RAM, cámara trasera de 10 megapíxeles y Android 4.3 Jelly Bean. Motorola ya ha anunciado que el smartphone será ensamblado en los Estados Unidos.
Source: Ya es oficial, el Moto X de Motorola será presentado el 1 de Agosto en Nueva York
Samsung Galaxy Note II To Skip Android 4.2.2 While The Galaxy Note III Makes A Guest Appearance In Picasa | Androidheadlines.com
Here are some news for current and future Samsung Galaxy Note users. I mean current for those with a Note II and future for those waiting for the Note III to be launched.In the case of the former, it appears that Samsung has decided to skip Android 4.2.2 and go directly to Android 4.3, which should be released soon, there’s been leaks of the Android 4.3 ROM for both the Samsung Galaxy S IV Google Play edition and the Nexus 4 so it can’t be that far off. This news come from Telstra, an Australian carrier, who’s update schedule has been updated with this info:Samsung have elected globally to skip the 4.2.2 update for this device and will instead go to a newer version of Android. No schedule has been provided for this update.While Telstra is talking about the Galaxy Note II 4G, we can expect the same behavior from Samsung to every Note II out there.
Currently, only the Galaxy S IV is running Android 4.2.2 on Samsung’s lineup, so we might see other phones skip this version as well, probably the Galaxy S III will go straight to 4.3 and makes things easier for both users and Samsung.As for those waiting for the Galaxy Note III to be announced, it’s code made another appearance, this time in Picasa (why is Picasa still alive when Google moved everything to Google+?). A picture has appeared with the code SM-N9005 attached to it, and while the picture doesn’t say much, it’s one more thing that keeps us interested until the release of the device. The N9005 supposedly corresponds to the LTE version of the device, but nobody thought Samsung wouldn’t do an LTE version of the Note III.
As a reminder, the Note III will feature a 5.7 inch Full HD super AMOLED display with an Octa-core processor (most likely the Exynos 5 5420) clocked at 2.3 GHz and a 13 megapixel camera with a Xenon flash. The overall design of the device should be the exact same design of the Galaxy S IV, only bigger, as we know Samsung does every year with their devices once they settle for a design.
Quoting : Samsung Galaxy Note II To Skip Android 4.2.2 While The Galaxy Note III Makes A Guest Appearance In Picasa | Androidheadlines.comThursday, July 18, 2013
Wednesday, July 17, 2013
Google sends press invites for July 24th event, new Nexus 7?
Stop the presses! Google has just began sending out press invites for a mysterious July 24th event. They’re calling it breakfast with Sundar Pichai, you guys may know him as the new Android chief who recently took over for Andy Rubin, and also continues working with Chrome.No word on what they have planned, but expect we’re thinking the long rumored Nexus 7, Android 4.3 and possibly even the Moto X will make an appearance. Our flight is booked, and we’ll bring the latest as it unfolds. Don’t worry if you can’t make it, Google is also planning to livestream the event as well.
Source : Google sends press invites for July 24th event, new Nexus 7?Tuesday, July 16, 2013
AMD FX-9560 5GHz CPU hits shelves in gaming PCs - SlashGear
AMD‘s flagship 5.0 GHz processor, the AMD FX-9560, has gone on sale, though the chip won’t be available as a standalone part for some time. The company will instead offer the new processor through various PC builders, including iBUYPOWER and Maingear, for those who want to be able to tell their friends they have the first commercially-available 5GHz chip.
Back when it was first announced, in June, the FX-9000 series prompted no small amount of questions as to the necessity of such a high clock speed. Whereas, at one time, the gigahertz race was an integral part of AMD and Intel’s battle for computing dominance, in recent years the focus has evolved to consider more real-world relevant tasks.
That’s gone hand in hand with GPU-accelerated processing, where chips that would normally be used for rendering high-resolution games are instead turned to parallel crunching through huge sets of data. AMD itself is experimenting with the idea, as part of its Heterogeneous Computing push.In contrast, the FX-9560 is about raw speed. That’s still going to appeal to some users, with AMD hoping they’ll head down to Canada Computers, CyberPower, iBUYPOWER, Digital Storm, Extreme PC, Maingear, Memory Express, NCIX, Origin PC, Puget Systems, or Velocity Micro, which are all signed up to use the new processor.Under the hood the chip has eight of AMD’s Piledriver cores, and comes unlocked for easy overclocking; AMD even supplies the software to do it. However, gamers shouldn’t get too carried away: if they break their processor with an ill-advised overclock, they won’t be covered by AMD’s warranty.
Monday, July 15, 2013
Sunday, July 14, 2013
Saturday, July 13, 2013
Moto X vendría con materiales personalizables: Madera, Cerámica y más
Source : Moto X vendría con materiales personalizables: Madera, Cerámica y más - Android Zone
Friday, July 12, 2013
Moto X makes public debut courtesy of Google’s Eric Schmidt - Android Community
As if there hadn’t been enough hype surrounding the Moto X, it looks like we now have a true in-the-wild sighting. Though, given the circumstances this one can hardly be considered a leak. Instead what we have is Google’s Eric Schmidt simply using the handset. These images come by way of the annual Allen & Co. conference and as you will see throughout this post — are showing the Moto X in white.
We had already seen images (of pieces) of the Moto X in white so this color doesn’t come as much of a surprise. With that in mind, given most of the leaks seem to be showing the handset in matte black, it is somewhat refreshing to see something different. Not to mention, something that looks a bit more like a finished product.
The white Moto X does remind us of the white Nexus 4, which has the white color on the back and sides with the front face completely black. Otherwise, these images seem to match up with the recent leaked images. You can clearly see the headphone jack centered on the top of the handset and the camera lens, flash and Motorolalogo (centered from left to right) on the back side.Also on the back sitting to the side of the camera lens is the speaker grill. This could also just be a case of the angles of the images, however the Moto X seen here appears much thinner as compared to some of those earlier leaks. The disappointing, but not all that surprising part here deals with the specs and the fact we have seen very little.
Earlier reports have suggested the handset has a 4.7-inch HD display and a dual-core 1.7GHz Snapdragon S4 Pro processor. Perhaps the key here will be the reportedly large marketing budget that Motorola has planned to promote the Moto X. Well, that or maybe people will flock to it because of the ability to customize the
Source : Moto X makes public debut courtesy of Google’s Eric Schmidt - Android CommunitySuperman memory crystal: 5D nano-glass to preserve data for million years — RT News
A research group in Britain has recorded data into a crystal of nanostructured glass. This future storage with practically unlimited lifetime and capacity exceeding Blu-Ray’s by 2,800 times might save civilization’s data for aliens if humankind is gone.
A group of scientists from University of Southampton has developed a ‘five-dimensional’ optical memory, having experimentally proven a possibility of recording data into nanostructured glass using a high speed (femtosecond) laser, which creates self-assembled nanostructures in fused quartz.
The creators of 5D memory has dubbed their invention ‘Superman memory crystal’, following the ‘memory crystals’ used in a number of movies featuring the superhero.
The method is called 5D because in addition to the three dimensional position of these nanostructures their refraction and polarization characteristics work as two additional parameters.
The newly-developed storage promises unprecedented data capacity of 360 Terabyte for a DVD-sized disc. The maximum capacity of a latest generation quad-layer Blu-Ray DVD is “only” 128 Gigabytes. The largest heat-assisted magnetic recording hard drive (HAMR), yet to be commercially produced, will have about 20 terabytes per disc.
Glass storage could preserve data for millions of years whereas a DVD guarantees only about seven years of faultless playback.
The nanostructured glass remains stable if exposed to temperatures up to 1,000°C.
“We are developing a very stable and safe form of portable memory using glass, which could be highly useful for organizations with big archives. At the moment companies have to back up their archives every five to ten years because hard-drive memory has a relatively short lifespan,” said the head of the project Jingyu Zhang, pointing out that museums and national archives with their huge numbers of documents are going to be the first to benefit.
A joint project of University of Southampton’s Optoelectronics Research Centre (ORC) and Eindhoven University of Technology has presented ‘5D Data Storage by Ultrafast Laser Nanostructuring in Glass’ report at the Conference on Lasers and Electro-Optics (CLEO’13) in San Jose, California.
The ORC’s physical optoelectronics group supervisor Prof. Peter G. Kazansky, follower of the Nobel Prize laureate for the invention of laser, Aleksandr Prokhorov, shared that “It is thrilling to think that we have created the first document which will likely survive the human race. This technology can secure the last evidence of civilization: all we’ve learnt will not be forgotten.”
Technology similar to polarized sunglasses
Technically speaking, the process appears as follows. A femtosecond laser that produces extremely short (280 femtoseconds – or 280 quadrillionths of a second) and intense pulses of light encrypts data file into layers of nanostructured dots inside a quartz glass. The layers are placed very close, with mere five micrometers (one millionth of a meter) between them.
These light impulses modify polarization and refraction of self-assembled dots as the light travels through the glass, somehow similar to the principle used in polarized sunglasses. Later the information encoded in dots’ 5D parameters can be read using an laser scanning device similar to the one used to read CD, DVD and Blu-ray discs and an optical microscope capable of untangling the polarized light reflected by the three-bit spots.
So far there is no talk about re-writing glass discs so they are going to be write-once-read-many (WORM).
Unlike modern DVD and Blu-Ray disks which record data on up to four layers, the 5D data storage will have hundreds of layers (around 400 layers for standard 1.2 mm CD), but will be made of glass instead of plastic encasing metal spraying with data.
So far the developers reported of a successful recording and reading of a 300kb text file on three layers of glass, but this is regarded only as a technological demonstration of this ground-breaking new technology with a very bright future.
Source : Superman memory crystal: 5D nano-glass to preserve data for million years — RT News
Thursday, July 11, 2013
Nokia Lumia 1020 PureView official: 41MP Windows Phone 8 - SlashGear
Nokia has officially announced the Nokia Lumia 1020, the company’s latest Windows Phone 8 handset and the first to use a 41-megapixel PureView camera system. Building on the pixel-oversampling technology of the original Nokia 808 PureView, the Lumia 1020 squeezes the camera into a smaller – though still chunky – form-factor, complete with a Xenon flash and new Pro Camera app with more control over manual settings. It’s headed to AT&T later this month, for $300 on-contract.
On the phone side, there’s a 4.5-inch AMOLED HD+ 1280 x 768 display topped with Gorilla Glass 3 and packing a sunlight readability mode for easier outdoor use. Like the Lumia 925 and 920, it also supports gloved use, thanks to a high-sensitivity touchscreen.
inside, there’s a dualcore 1.5GHz Qualcomm Snapdragon S4 processor paired with 2GB of RAM and 32GB of internal storage. Connectivity includes LTE, HSPA+, and GSM/EDGE, along with WiFi a/b/g/n, Bluetooth 3.0, GPS, and NFC. The 2,000 mAh battery is non-user-accessible, and there’s no integrated wireless charging; instead, Nokia will offer snap-on wireless charging covers, similar to how it did with the Lumia 925, which can be used to add the ability to the high-resolution smartphone.
It’s the camera we’re most excited about, unsurprisingly, and it’s there where Nokia has put in the most effort. The 41-megapixel sensor uses the same PureView system as the 808 did, clustering data from multiple proximate pixels together and producing normally-sized images with more accurate colors and brightness, and less noise.
There’s also optical image stabilization and a backside-illuminated sensor, Zeiss optics, and a new Pro Camera app which gives greater than usual manual control over settings like exposure, ISO, and more. Above the display there’s a 1.2-megapixel camera with a wide-angle lens.
However, unlike on the 808, the Lumia 1020 is able to simultaneously snap both a low- and a full-resolution image. That gives an instantly-sharable 5-megapixel picture at a cellular-data-reasonable resolution, as well as a full image at around 40-megapixels. With the latter, the Lumia 1020 can offer a lossless digital zoom after the still is taken: effectively, a crop is taken out of the full-resolution shot, with no need to artificially enlarge. Up to a 3x lossless digital zoom is supported.
As for video, the Lumia 1020 is capable of recording 620p HD footage while also offering 6x digital lossless zooming; the Windows Phone can also record 1080p Full HD video, though with less of a zooming range. There’s stereo audio recording, too, with Nokia promising better bass capture than rival phones thanks to its Rich Recording system.
Nokia hasn’t forgotten accessories, either, with the Nokia Camera Grip PD-95G. That has an integrated battery, extending the Lumia 1020′s runtime – estimated at 13.3hrs of talktime, 16 days standby, 6.8hrs of video playback, or 63hrs of music – and a two-stage camera key. It also adds a tripod mount for more professional use. Without the case, the Lumia 1020 is 130.4 x 71.4 x 10.4 mm and 158g.
The Nokia Lumia 1020 will go on sale on July 26, priced at $299.99, as an AT&T exclusive in the US. Preorders – for the black, white, and yellow versions – will be offered from July 16.
PS4 digital library sharing gives you access from any console - SlashGear
Since the PlayStation 4 and Xbox One are almost identical as far as performance specifications go, it’s merely just a war between features and functionality. Both sides are trying to win over the hearts of gamers with innovation new features that aim to change the landscape of gaming. Sony thinks they have a pretty unique solution in the bag.
The company’s R&D senior team boss Neil Brown announced at Sony’s Develop Conference that PS4 gamers can access their purchased games on any PS4 console. Brown also touted the new “play as you download” feature, where you can play games as they’re downloading them to the console.Essentially, gamers can log in to their accounts from any PS4 console, and they can start playing the first bits of any digitally-purchased game that’s available in their library, even if it’s not from their own console at home. If your friend doesn’t have a specific game that you want to play, the “play as you download” feature is about as good as it gets.The background downloading while gamers begin playing their games is made possible simply by background processes. Brown says it’s a similar method to what Blu-ray players use, and chunks of the game are copied automatically to the hard drive. After the first few minutes, the game is able to begin playing.Xbox One has a similar feature where you can begin playing games while they download and install onto the console’s hard drive. However, one huge benefit for the PS4 at this point is the low price tag. Sony’s console will only cost $399 when it launches later this year, undercutting the Xbox One by $100.
Mercado Telecom | LG lança tela de 5,2 polegadas LCD Full HD mais fina e compacta do mundo
Enquanto a tendência hoje é que as telas de nossos smartphones fiquem cada vez maiores, os mesmos smartphones tendem a que ficar cada vez mais finos e a LG agora deu uma grande contribuição para isso.
A empresa acaba de anunciar a tela de LCD Full HD mais fina do mundo. Com 5.2 polegadas e apenas 2.2mm de espessura, o display chega a ser 30% mais fino que os atuais graças à uma tecnologia da LG chamada Advanced-One-Glass Solution, que consiste em inserir uma camada de circuitos flexíveis entre o vidro e o sensor de toques.
A tela conta ainda com apenas 2.3mm de borda, deixando praticamente nenhum espaço entre a lateral e a tela em si. Outro ponto interessante é que a tela é capaz de emitir 535 nits de brilho. Para efeito de comparação, o Samsung Galaxy S4 fica em torno de 300 nits.
O interessante na produção de uma tela tão fina não resulta apenas na possibilidade de smartphones mais finos, mas também no espaço que agora ficará vazio e poderá ser ocupado por uma bateria maior, uma das principais reclamações dos usuários de smartphones.
Source :Mercado Telecom | LG lança tela de 5,2 polegadas LCD Full HD mais fina e compacta do mundo
Wednesday, July 10, 2013
Nexus 7 II podría llegar inminentemente con Snapdragon 600, y Android 5.0 Key Lime podría ver la luz en octubre
Todo son rumores, así que no os toméis al pie de la letra las informaciones. Sin embargo, nos hemos visto obligados a traeros la noticia porque las fechas y los datos coinciden, y porque la renovación de la gama Nexus no debería estar muy lejos.Lo primero a tratar es la segunda generación de la tableta pequeña de Google, la Nexus 7, que al parecer ya estaría en el horno bajo el código K009 y de la que se filtran varias de sus especificaciones.El nuevo Nexus 7, según la fuente, montará un Qualcomm Snapdragon 600 que dará vida a una pantalla de 7 pulgadas con resolución FullHD. Además, esta vez si contará con doble cámara, de 5 y 1.2 megapíxeles respectivamente, y el hardware se completa con 2 GB de memoria RAM y un modelo con conectividad LTE.No queda claro cuando podría presentarse y empezar su comercialización, pero parece que la versión 4.3 Jelly Bean de Android se estrenará oficialmente con su lanzamiento. Viendo los últimos movimientos de Google y las presentaciones de sus anteriores dispositivos, podría ser anunciado desde el blog de Google, sin eventos y con una llegada inminente a Play Store.Por si esto nos parecía poco, la fuente también habla del esperado Android 5.0 Key Lime Pie, quellegaría cumpliendo el calendario para octubre a bordo del Nexus 5, dispositivo que parece fabricará de nuevo LG basándose en la plataforma del G2.Si debemos tomárnoslo en serio o no lo dirá el tiempo, aunque las fechas y los datos parecen coincidir, a excepción de la confirmación ya olvidada por parte de Motorola de que serían ellos quien estrenasen Android 5.0 con su X Phone.
Source : Nexus 7 II podría llegar inminentemente con Snapdragon 600, y Android 5.0 Key Lime podría ver la luz en octubre
Chrome 28 para Android, ahora pantalla completa en tablets y traductor
Con una semana de retraso según lo esperado, el navegador Chrome para Android lanza en Google Play la versión 28 de forma estable con algunas de las mejoras que se han podido disfrutar en las últimas semanas gracias a su Beta.
La primera novedad de Chrome 28 para Android añade su navegación a “pantalla completa” en tablets de la misma forma que lo hizo para móviles en la versión anterior. Ahora al hacer un desplazamiento vertical la barra de direcciones se esconderá para mostrar más contenido de las páginas webs.
Otras novedades son mejoras de estabilidad, corrección de errores y una nueva interfaz para los idiomas escritos de derecha a izquierda (RTL) como el árabe, persa o hebreo. Además, parece que en próximos días habilitarán la compresión de datos para ayudarnos a consumir menos datos cuando navegamos.
Source: Chrome 28 para Android, ahora pantalla completa en tablets y traductor
WSJ: Moto X will be available on all major US carriers, backed by $500M marketing blitz | The Verge
he upcoming Moto X smartphone represents something of a rebirth for Motorola, and Google is reportedly willing to spend top dollar to get that message across. According toThe Wall Street Journal, Mountain View is prepared to spend upwards of $500 million on the marketing campaign for its customizable, assembled-in-the-USA flagship. That budget is said to cover the United States as well as some international countries where the Moto X will be sold. Motorola has already turned on the hype machine, recently placing a full-page ad in various US newspapers crediting the Moto X as "the first smartphone you can design yourself." Those customization options include a choice of colors for the front and back, as well as engraving.
Availability of the Moto X is expected to be widespread for US buyers. All four major mobile carriers in the United States — Verizon Wireless, AT&T, Sprint, and T-Mobile — will carry the Moto X sometime this fall, The Wall Street Journal report claims. Even better, under Google's ownership, Motorola has reportedly convinced the providers to dial back the amount of bloatware that will ship on the hardware. We've collected everything we know (so far) about Moto X and Motorola's other upcoming products here.
Source: WSJ: Moto X will be available on all major US carriers, backed by $500M marketing blitz | The Verge
Google+ Rolling Out More Updates, Allowing you to see What Your Friends +1'd | Androidheadlines.com
Tuesday seems to be Google’s day to announce updates and changes to their services. Today, they have announcedthat they’ll be highlighting posts that have been +1′d by people in your circles on your stream, as well as highlighting some of your popular posts to your friends in their main stream on Google+. Earlier today, we talked about how Google+ is now the second largest and most popular social network, and this is going to allow people to find even more content and use Google+ even more.
These new features are said to be very similar to how Facebook highlights posts you’ve “Liked” on their network. As you can see in the image above, you’ll be able to see who from your circles have +1′d that post. Which will be shown right above the content.
This content might be some new content that probably would have never shown up in your stream, allowing people to have more chances to have their posts go viral or even hit Whats Hot on Google+. The good thing here is that you can go into your Google+ settings and determine who can see what you +1 on Google+. So only people in the circles you’ve determined can see what content you’ve +1′d. Which is much more private than what Facebook is doing, or is it?
It seems these days that Facebook, Twitter and Google+ are all copying features from each other. Google+ added hashtags after Twitter, and then Facebook followed suite. Facebook added larger pictures after Google+ did, and Twitter added cover photos after Facebook and Google+ did. See the cycle here?
How are you liking this new feature from Google+? Does it seem like an invasion of privacy? Or is it something good for Google+? Let us know your thoughts down in the comments.
Source: Google+ Rolling Out More Updates, Allowing you to see What Your Friends +1'd | Androidheadlines.com
Tuesday, July 9, 2013
LG Optimus G2 detailed in leaked pictures | Android and Me
Expected to be officially unveiled on August 7, Engadget has just received a handful of pictures from an anonymous source detailing the Optimus G2, strange backside volume rocker and all.
The pictures don’t provide any information on technical specs, but do share a bit on how the Optimus G2 will look and feel. LG is headed the way of the Nexus 4 with the G2, giving the device itself a more rounded shape with a dark chrome bezel. The LG logo is placed near the bottom of the face of the device, right below the area reserved for on-screen buttons, with no decorations up top. Towards the back of the device, you can see the strange plus and minus switch, which we assume will be a multipurpose volume switch.
Software wise, we see that the Optimus G2 will use a white camera UI, which looks rather nice, and a fully transparent notification bar and background for the on-screen buttons mentioned above.
All in all, the LG Optimus G2 looks like a great device. We’re excited to know more come August 7, just under a month away now.
Source: LG Optimus G2 detailed in leaked pictures | Android and Me
Lleva la apariencia iOS 7 a tu Android con jbOS7 - Android Zone
Desde que Apple presentó iOS 7, hubo una gran controversia. Se trata del cambio en la interfaz más grande en la historia de la plataforma y como en todo gran cambio hay algunos que lo apoyan mientras que otros lo resisten. El nuevo SO fue presentado el pasado 10 de junio pero no llegará a los iPhone hasta otoño. Dado que Android es un sistema operativo abierto, podemos llevar la apariencia de la nueva versión de iOS a nuestros dispositivos ahora mismo gracias a jbOS 7 (Jelly Bean OS 7), un MOD que trabaja sobre Nova Launcher.
Se trata de una pantalla de inicio con aplicaciones y dos pantallas especiales que actúan como apps. Al pulsar sobre el calendario, nos lleva a la pantalla del calendario, lo mismo sucede con el ícono del clima. Además de la estética, jbOS7 posee una pantalla de desbloqueo muy similar a iOS 7 para completar el combo.
Cabe aclarar que con este tema tu dispositivo seguirá funcionando como Android, no se trata de llevar iOS 7 a tu teléfono sino simplemente de llevar su estética.
Los pasos para su instalación se detallan en el siguiente video:
Mobile Communication: From 1G to 4G
Dr J.D. Jain
Any radio telephone capable of operating while moving at any speed, battery operated and small enough to be carried by a person comes under the mobile communication systems. These communication systems may have different facilities. The different types of mobile communication systems are mobile two-way radio, public land radio, mobile telephone and amateur (HAM) radio.
Mobile two-way radios are one-to-many communication systems that operate in half-duplex mode, i.e., push to talk. The most common among this type is citizen band (CB) radio, which uses amplitude modulation (AM). It operates in the frequency range of 26-27.1 MHz having 40 channels of 10 kHz. It is a non-commercial service that uses a press-to-talk switch. It can be amplitude-modulated having double-sideband suppressed carrier or single-sideband suppressed carrier.
Public land mobile radio is a twoway FM radio system, used in police, fireand municipal agencies. It is limited to small geographical areas.
Mobile telephones offer full-duplex transmission. These are one-to-one systems that permit two simultaneous transmissions. For privacy, each mobile unit carries a unique telephone number.
Amateur (HAM) radios cover a broad frequency band from 1.8 MHz to above 30 MHz. These include continuous wave (CW), AM, FM, radio teleprinter, HF slow-scan still picture TV, VHF or UHF slow-scan or fast-scan TV, facsimile, frequency-shift keying and amplitude-shift keying.
Present and past of mobile communications
Before I narrate the journey from 1G to 4G, let me explain the important technologies behind the phenomenal growth of mobile communication systems. Since the commercial introduction of advanced mobile phone system (AMPS) service in 1983, mobile communication systems have witnessed an explosive growth. The most important breakthrough was the cellular concept.
Cellular concept. The advent of cellular operation brought frequency reuse capabilities. Advances in wireless access, digital signal processing, integrated circuits, increased battery life, etc led to exponential growth of personal communication services.
Cellular system works as follows: An available frequency spectrum is divided into discrete channels, which are assigned in groups to geographic cells covering a service area. The discrete channels are capable of being reused in different cells with diameters ranging from 2 to 50 km. The service area is allotted a radio frequency (RF) transmitter, whereas adjacent cells operate on different frequencies to avoid interference.
Cellular telephones began as a simple two-way analogue communication system using frequency modulation for voice and frequency-shift keying for transporting control and signaling information. Other cellular systems are digital cellular system, cordless telephony, satellite mobile and paging. Analogue cellular systems fall in the first-generation(1G) category and digital cellular low-power wireless fall in the second-generation (2G) category.
Analogue cellular phone. In 1970, Bell Labs in New Jersey proposed a cellular telephone concept as advanced mobile telephony system (AMPS). AMPS is a standard cellular telephone service placed into operation on October 13, 1983 by Illinois Bell. It uses narrow-band FM with a usable audio frequency band of 300-3 kHz and maximum frequency deviation of ±12 kHz for 100 per cent modulation. According to Carson’s rule, this corresponds to 30 kHz.
AMPS uses frequency-division multiple access (FDMA), where transmissions are separated in the frequency domain. Subscribers are assigned a pair of voice channels (forward and reverse) for the duration of their call. Analogue cellular channels carry both voice using FM and digital signaling information using binary FSK.
Digital cellular system. It provides improvements in both capacity and performance. FDMA uses a frequency canalisation approach to spectrum management, while time-division multiple access (TDMA) utilises a time-division approach. The entire available cellular RF spectrum is sub-divided into narrow-band radio channels to be used as a one-way communication link between cellular mobile units and base stations.
Multiple access technologies for cellular systems
Generally, a fxed amount of frequency spectrum is allocated to a cellular system. Multiple access techniques are deployed so that the users can share the available spectrum in an efficientmanner.
For wireless communication, multiplexing can be carried out in three dimensions: Time (TDMA), frequency (FDMA and its variation OFDMA) and code (CDMA).
In TDMA the available spectrum is partitioned into narrow frequency bands or frequency channels, which, in turn, are divided into a number of time slots. In case of North American digital cellular standard IS-136, each frequency channel (30 kHz) is divided into three time slots, whereas in European digital cellular system GSM each frequency channel (200 kHz) is divided into eight time slots. Guard bands are needed both between frequency chan-nels and time slots.
In FDMA, users share the available spectrum in a frequency band called trafficchannel. Different users are assigned different channels on demand basis. The user’s signal power is concentrated in a relatively narrow frequency band. All the analogue cellular systems used FDMA system.
OFDM is a multi-cellular transmission technique where a data stream is carried with many lower-rate subcarrier tones. It has been adopted in mobile communications to combat hostile frequency-selective fading and has been incorporated into wireless network standards.OFDM is a multi-cellular transmis-sion technique where a data stream is carried with many lower-rate sub-carrier tones. It has been adopted in mobile communications to combat hostile frequency-selective fading and has been incorporated into wireless network standards.
OFDM combines the advantages of coherent detection and OFDM modulation and has many merits that are critical for future high-speed transmission systems. By using up/down conversion, electrical bandwidth requirement can be greatly reduced for the OFDM transceiver, which is extremely attractive for high-speed circuit design where electrical signal bandwidth dictates the cost. Lastly, signal processing in the OFDM transceiver can take advantage of efficient algorithm of fat Fourier transform (FFT)/inverse FFT, which suggests that OFDM has superior scalability over channel dispersion and data rate.
Digital modulation keying
Communication systems often involve modulation of a carrier, which results in a bandpass waveform. A digital signal can be used to modulate the amplitude, frequency or phase of a sinusoidal carrier producing three different forms of digital modulation: amplitude-shift keying (ASK), frequency-shift keying (FSK) and phase-shift keying (PSK). In addition to these basic techniques, there are some modulation schemes that employ a combination of amplitude and phase modulation. It may be noted that unlike ASK signal, PSK transmission is polar. At the same time, ASK is a linear modulation scheme, whereas PSK is a non-linear modulation scheme. PSK has a superior performance over ASK.
Quadrature phase-shift keying (QPSK). Digital modulation techniques mentioned above are spectrally inefficientin the sense that the available channel bandwidth is not fully used. Spectral efficiencycan be improved by using QPSK. It is a system for two message sources. In this system modulation carriers in phase quadrature are combined to form the output waveform. In QPSK the amplitude of the modulator waveform and modulator gains are made as nearly equal as possible.
Differential phase-shift keying (DPSK). DPSK is a modification of PS that avoids the need to provide synchronous carrier required for detection of PSK signals. It is an ingenious technique whereby the carrier reference is derived from the received waveform in the preceding bit interval by use of a 1-bit delay. In essence, the received waveform delayed by 1-bit duration serves as its own reference.
Data transmission using packet switching
This is done by supplying various addressed packets, which are interconnected to have the conversation. New dedicated paths are created for sending the data. From the multiple paths to the destination, any path can be used to send data. Cellular digital packet data was designed for optimal operation with an analogue cellular system, especially AMPS.
Short message service. Short message service is the most common packet service that is supported on digital cellular networks like GSM, IS-136, EDGE and PDC (packet data service). It is a store-and-forward/packet mode service that provides inter-working with the various applications and services within a fixednetwork. For message transfer between relevant network entities, control and signaling channels (instead of normal traffic channels) ar generally used for data transmission.
General packet radio service (GPRS). GPRS essentially represents add-on capabilities to the basic voice-optimised cellular network that nevertheless maintain the essential characteristics of radio-access technology.
Enhanced data rates for GSM evolution (EDGE). In order to enhance the data handling capabilities of 2G service, radio-access portion had to be modifed. This modifcation was evolved in Europe in the form of EDGE. EDGE also supports a link adaptation mechanism that selects the best combination of modulation and encoding schemes based on the timevarying link quality.
EDGE concept applies to both circuit-mode and packet-mode data and is sufficiently generic for appliction to other digital cellular systems. It works in the 200kHz bandwidth with one or more high-level modulation schemes and a range of efficient coding methods. Modulation schemes are offset QPSK and offset 16 QAM.
Spread spectrum
It is a special communication technique that purposefully uses much more RF bandwidth than necessary to transmit a signal. This helps in improving the signal-to-noise (S/N) ratio. The main advantages of this technique are secure communication and resistance to intentional jamming. There are 75 channels in the 2400-2483.3MHz band.
There are two methods of perform-ing spread spectrum:
Frequency hopping. This technique spreads the narrow-band signal as a function of time. The transmitted frequency is changed to a different pre-assigned channel several times per second (hopped). The order in which the pre-assigned channels are selected is ‘pseudo random.’ In other words, the channel order is seemingly random but actually repeats itself at a definedinterval. The specificorder in which frequencies are occupied is a function of code sequence and the rate of hopping from one frequency to another is a function of information rate.
Direct sequence. This technique spreads a signal by expanding the signal over a broadband portion of the radio band. It uses a locally generated pseudo noise (PN) code to encode digital data to be transmitted. The most practical all-digit version is direct sequence. Binary phase-shift keying is the simplest and most often used modulation technique.
One of the most important features of spread-spectrum signals is that these contain a large number of very different signaling formats, used for communicating data symbols. It means that the receiver which detects one of these formats cannot detect any other format within a single message. The number of formats used in a spread-spectrum system is called multiplicity factor of the communication link and amounts to thousands.
CDMA. CDMA is a form of direct-sequence spread-spectrum technology that allows many users to occupy the same time and frequency allocations in a given band/space. CDMA assigns each user a unique spreading code to spread the baseband data before transmission, in order to help differentiate signals from various users in the same spectrum. It is the platform on which 2G and advanced 3G services are built.
After speech, the codec converts voice into digital signal. CDMA spreads the voice stream over the full 1.25MHz bandwidth of the CDMA channel, coding each stream separately. The receiver uses a correlator to despread the wanted signal, which is passed through a bandpass filter.Unwanted signals are not despread and not passed through the filter.
The rate of the spreading signal is known as the ‘chip rate’ as each bit in the spreading signal is known as ‘chip.’ All 2G networks support only single-user data rates of the order of 10 kbps, which is too slow for rapid e-mail and Internet browsing.
CDMA provides more than ten times the capacity of the analogue AMPS and fivetimes the calling capacity of GSM and TDMA systems. It requires fewer cell sites than GSM and TDMA.
Personal communication system
Personal communication system (PCS) is a new class of cellular telephone system such as AMPS. PCS systems are a combination of cellular telephone network and intelligent network, which is the entity of super-simple transfer (SST) inter-office protocol tha distinguishes physical components of the switching network such as signal service point, signal control point and signal transfer point from the services provided by SST network.
In essence, PCS is the North American implementation of European GSM standard. GSM utilised its own TDMA access methods and provided expanded capacity and unique services such as caller ID, call forwarding and short messaging. A critical feature was seamless roaming, which allowed subscribers to move across provider boundaries. The effort was directed towards second-generation cellular systems.
In 1990, a second frequency band was specified. This band included twodomains—1710-1785 MHz and 1805-1880 MHz, i.e., twice 75 MHz; three times as much as the primary 900MHz band.
Digital enhanced cordless telecommunication (DECT). DECT is a type of PCS system. DECT standard was developed by European Telecommunication Standards Institute (ETSI) for wireless PABX data LAN applications that represent closed environments requiring minimal open cordless access, since it was essential that products from different vendors not only coexist but interwork with each other.
DECT system has a TDMA/TDD frame structure with 24 slots that are equally allocated for downlink and uplink operation. DECT specifiesboth simplex (half-slots) and duplex (full slot) operation. Higher data rates are achieved by utilising multilevel modulation. The basic modulation scheme is a two-level Gaussian filled frequency-shif keying (GFSK), which is supplemented with 8-level modulation scheme leading to as high as 2.88 Mbps per carrier.
GSM
Global system for mobile communications (GSM) was developed by the Groupe Special Mobile, which was an initiative of the Conference of European Post and Telecommunications (CEPT) administrations. GSM was firs devised as a cellular system in a specific 900MHz band called the primary band. This primary band includes two sub-bands of 25 MHz each, 890-915 MHz and 935-960 Mhz.
GSM systems like Iridium, Globalstar and ICO use constellations of low-earth orbit (LEO) or medium-earth orbit (MEO) satellites and operate as overlay networks for existing cellular and PCS networks. Using dual-mode, these extend the coverage to any and all locations on the earth’s surface.
International Mobile Telecommunication-2000 (IMT-2000) is a standard developed by ITU for 3G. It ensures global mobility in terms of global seamless roaming and service delivery. An appreciation of the role of numbering and identities in mobility management, international roaming, call delivery, and billing and charging is important in understanding the operation of mobile and personal communication networks.
Personal communication satellite service (PCSS) uses LEO satellite repeaters incorporating QPSK modulation and both FDMA and TDMA.
The main advantages of GSM are international roaming (in harmony with ISDN principles assuring inter-working between ISDN and GSM) and features like privacy and encryption, frequency hopping, discontinuous transmission and short message service. Other facilities include call forwarding, barring, waiting, hold and teleconferencing.
The basic architecture comprises a network sub-system, base station sub-system, mobile stations, and system interworking and interfaces.
A subscriber identity module (SIM) is required to activate and operate a GSM terminal. The SIM may be contained within the mobile station or it may be a removable unit that can be inserted by the user in his mobile set.
New developments along the way
Before we proceed to evolution from 1G to 4G, let me touch upon the new developments that took place in 1G to 4G.
Global positioning system (GPS). GPS is a reliable navigational aid available anywhere on the earth, operating in all weather conditions 24 hours a day. It can be used by marine, airborne and land users. GPS technology was developed in 1983.
GPS consists of three segments:
Space segment. GPS consists of 24 NAVSTAR satellites along with three spare satellites orbiting at 20,200 km above the earth’s surface in six circular orbital planes with a 12-hour orbital period each. These satellites operate at L1 band (1.575 GHz) continuously broadcasting navigational signals called coarse acquisition code. These codes can be received by anyone for decoding and findingnavigational parameters like longitude, latitude, velocity and time.
Control segment. It consists of a master control station (MCS) and a number of smaller earth stations called monitoring stations located at different places in the world. Monitoring stations track satellites and pass on the measured data to the MCS. The MCS computes satellite parameters (called ephemeris) and sends them back to the satellite, which, in turn, broadcasts to all GPS receivers.
User segment. The user segment consists of all moving and stationary objects with GPS receivers. A GPS receiver is a multi-channel satellite receiver that computes every second its own location and velocity.
Bluetooth. Compared to WLAN technologies, Bluetooth technology aims at so-called ad-hoc piconets, which are local-area networks with a very limited coverage and without the need for an infrastructure. The term ‘piconet’ is a collection of Bluetooth devices that are synchronised to the same hopping sequence. One device in the piconet can act as master and all other devices connected to the master act as slaves. The master determines the hopping pattern and the slaves have to synchronise to this pattern. The hopping pattern is determined by the device ID—a 48-bit worldwide unique identifier.The phase in the hopping pattern is determined by the master’s clock. All active devices are assigned a 3-bit active member address.
All parked devices use an 8-bit parked member address. Devices in standby mode do not need an address. The goal for Bluetooth development was to use a single-chip, low-cost, radio-based wireless network technology for laptops, notebooks, headsets, etc.
Bluetooth operates in the 2.4GHz ISM band. However, MAC, physical layer and the offered services are completely different. Bluetooth transceivers use Gaussian FSK for modulation and are available in three power classes: Class 1 (max. power 100 mW), class 2 (max. power 2.5 mW) and class 3 (max. power 1 mW).
Journey from 1G to 4G
1G system. 1G specifications were released in 1990 to be used in GSM. 1G systems are analogue systems such as AMPS that use FDM to divide the bandwidth into specificfrequencies that are assigned to individual calls.
2G system. These second-generation mobile systems are digital and use either TDMA or CDMA method. Digital cellular systems use digital modulation and have several advantages over analogue systems, including better utilisation of bandwidth, more privacy, and incorporation of error detection and correction.
2.5G system. It was introduced mainly to add latest bandwidth technology to the existing 2G generation. It supports higher-data-rate transmission for Web browsing and also supports a new browsing format language called wireless application protocol (WAP). The different upgrade paths include high-speed circuit-switched data (HSCSD), GPRS and EDGE.
HSCSD increases the available application data rate to 14.4 kbps as compared to 9.6 kbps of GSM. By using four consecutive time slots, HSCSD is able to provide a raw transmission rate of up to 57.6 kbps to individual users.
GPRS supports multi-user network sharing of individual radio channels and time slots. Thus GPRS supports many more users than HSCSD but in a bursty manner. When all the eight time slots of a GSM radio channel are dedicated to GPRS, an individual can achieve as much as 171.2 kbps. But this has not brought any new evolution.
EDGE introduces a new digital modulation format called 8-PSK (octal phase-shift keying). It allows nine different air interface formats, known as multiple modulation and coding schemes, with varying degree of error control and protection. These formats are automatically and rapidly selectable. Of course, the covering range is smaller in EDGE than in HSCSD or GRPS.
3G system. To overcome the short-comings of 2G and 2.5G, 3G has been developed. It uses a wideband wireless network that offers increased clarity in conversations. Countries throughout the world are currently determining new radio spectrum bands to accommodate 3G networks. ITU has established 2500-2690MHz, 1700-1855MHz and 806-960MHz bands. Here the target data rate is 2 Mbps. The data is sent through packet switching. Voice calls are interpreted through circuit switching.
3G W-CDMA (UMTS). Universal Mobile Telecommunication System (UMTS) or W-CDMA assures backward compatibility with 2G and 2.5G TDMA technologies. W-CDMA, which is an air interface standard, has been designed for always-on packet-based wireless service, so that computers and entertainment devices may all share the same wireless network and connect to the Internet anytime, anywhere.
W-CDMA supports data rates of up to 2.048 Mbps if the user is stationary, thereby allowing high-quality data, multimedia, streaming audio, streaming video and broadcast type services to consumers. With W-CDMA, data rates from as low as 8 kbps to as high as 2 Mbps can be carried simultaneously on a single W-CDMA 5MHz radio channel, with each channel supporting between 100 and 350 simultaneous voice calls at once, depending on antenna sectoring, propagation conditions, user velocity and antenna polarisation.
Time slots in W-CDMA are not used for user separation but to support periodic functions. (This is in contrast to GSM where time slots are used to separate users). The bandwidth per W-CDMA channel is 4.4 to 5 MHz.
Since the global standard was diffiult to evolve, three operating modes have been specified:A 3G device will be a personal, mobile, multimedia communication device (e.g., TV provider redirects a TV channel directly to the subscriber’s phone where it can be watched). Second, it will support video conferencing, i.e., subscribers can see as well as talk to each other. Third, it will also support location-based services, where a service provider sends localised weather or trafficconditions to the phone or the phone allows the subscriber to findnearby businesses or friends.
3.5G. It supports a higher through-put and speed at packet data rates of 14.4 Mbps, supporting higher data needs of consumers.
4G system. It offers additional features such as IP telephony, ultrabroadband Internet access, gaming services and HDTV streamed multimedia. Flash-OFDM, the 802.16e mobile version of WiMax (also known as WiBro in South Korea), can support cellular peak data rates of approx. 100 Mbps for high-mobility communications such as mobile access and up to 1 Gbps for low-mobility communications such as nomadic/local wireless access, using scalable bandwidths of up to 40 MHz. The infrastructure for 4G is only packet-based (all-IP).
Mobile two-way radios are one-to-many communication systems that operate in half-duplex mode, i.e., push to talk. The most common among this type is citizen band (CB) radio, which uses amplitude modulation (AM). It operates in the frequency range of 26-27.1 MHz having 40 channels of 10 kHz. It is a non-commercial service that uses a press-to-talk switch. It can be amplitude-modulated having double-sideband suppressed carrier or single-sideband suppressed carrier.
Public land mobile radio is a twoway FM radio system, used in police, fireand municipal agencies. It is limited to small geographical areas.
Mobile telephones offer full-duplex transmission. These are one-to-one systems that permit two simultaneous transmissions. For privacy, each mobile unit carries a unique telephone number.
Amateur (HAM) radios cover a broad frequency band from 1.8 MHz to above 30 MHz. These include continuous wave (CW), AM, FM, radio teleprinter, HF slow-scan still picture TV, VHF or UHF slow-scan or fast-scan TV, facsimile, frequency-shift keying and amplitude-shift keying.
Present and past of mobile communications
Before I narrate the journey from 1G to 4G, let me explain the important technologies behind the phenomenal growth of mobile communication systems. Since the commercial introduction of advanced mobile phone system (AMPS) service in 1983, mobile communication systems have witnessed an explosive growth. The most important breakthrough was the cellular concept.
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Cellular system works as follows: An available frequency spectrum is divided into discrete channels, which are assigned in groups to geographic cells covering a service area. The discrete channels are capable of being reused in different cells with diameters ranging from 2 to 50 km. The service area is allotted a radio frequency (RF) transmitter, whereas adjacent cells operate on different frequencies to avoid interference.
Cellular telephones began as a simple two-way analogue communication system using frequency modulation for voice and frequency-shift keying for transporting control and signaling information. Other cellular systems are digital cellular system, cordless telephony, satellite mobile and paging. Analogue cellular systems fall in the first-generation(1G) category and digital cellular low-power wireless fall in the second-generation (2G) category.
Analogue cellular phone. In 1970, Bell Labs in New Jersey proposed a cellular telephone concept as advanced mobile telephony system (AMPS). AMPS is a standard cellular telephone service placed into operation on October 13, 1983 by Illinois Bell. It uses narrow-band FM with a usable audio frequency band of 300-3 kHz and maximum frequency deviation of ±12 kHz for 100 per cent modulation. According to Carson’s rule, this corresponds to 30 kHz.
AMPS uses frequency-division multiple access (FDMA), where transmissions are separated in the frequency domain. Subscribers are assigned a pair of voice channels (forward and reverse) for the duration of their call. Analogue cellular channels carry both voice using FM and digital signaling information using binary FSK.
Digital cellular system. It provides improvements in both capacity and performance. FDMA uses a frequency canalisation approach to spectrum management, while time-division multiple access (TDMA) utilises a time-division approach. The entire available cellular RF spectrum is sub-divided into narrow-band radio channels to be used as a one-way communication link between cellular mobile units and base stations.
Multiple access technologies for cellular systems
Generally, a fxed amount of frequency spectrum is allocated to a cellular system. Multiple access techniques are deployed so that the users can share the available spectrum in an efficientmanner.
For wireless communication, multiplexing can be carried out in three dimensions: Time (TDMA), frequency (FDMA and its variation OFDMA) and code (CDMA).
 FDMA, TDMA, and CDMA multiple-access techniques |
In FDMA, users share the available spectrum in a frequency band called trafficchannel. Different users are assigned different channels on demand basis. The user’s signal power is concentrated in a relatively narrow frequency band. All the analogue cellular systems used FDMA system.
OFDM is a multi-cellular transmission technique where a data stream is carried with many lower-rate subcarrier tones. It has been adopted in mobile communications to combat hostile frequency-selective fading and has been incorporated into wireless network standards.OFDM is a multi-cellular transmis-sion technique where a data stream is carried with many lower-rate sub-carrier tones. It has been adopted in mobile communications to combat hostile frequency-selective fading and has been incorporated into wireless network standards.
OFDM combines the advantages of coherent detection and OFDM modulation and has many merits that are critical for future high-speed transmission systems. By using up/down conversion, electrical bandwidth requirement can be greatly reduced for the OFDM transceiver, which is extremely attractive for high-speed circuit design where electrical signal bandwidth dictates the cost. Lastly, signal processing in the OFDM transceiver can take advantage of efficient algorithm of fat Fourier transform (FFT)/inverse FFT, which suggests that OFDM has superior scalability over channel dispersion and data rate.
Digital modulation keying
Communication systems often involve modulation of a carrier, which results in a bandpass waveform. A digital signal can be used to modulate the amplitude, frequency or phase of a sinusoidal carrier producing three different forms of digital modulation: amplitude-shift keying (ASK), frequency-shift keying (FSK) and phase-shift keying (PSK). In addition to these basic techniques, there are some modulation schemes that employ a combination of amplitude and phase modulation. It may be noted that unlike ASK signal, PSK transmission is polar. At the same time, ASK is a linear modulation scheme, whereas PSK is a non-linear modulation scheme. PSK has a superior performance over ASK.
Quadrature phase-shift keying (QPSK). Digital modulation techniques mentioned above are spectrally inefficientin the sense that the available channel bandwidth is not fully used. Spectral efficiencycan be improved by using QPSK. It is a system for two message sources. In this system modulation carriers in phase quadrature are combined to form the output waveform. In QPSK the amplitude of the modulator waveform and modulator gains are made as nearly equal as possible.
Differential phase-shift keying (DPSK). DPSK is a modification of PS that avoids the need to provide synchronous carrier required for detection of PSK signals. It is an ingenious technique whereby the carrier reference is derived from the received waveform in the preceding bit interval by use of a 1-bit delay. In essence, the received waveform delayed by 1-bit duration serves as its own reference.
Data transmission using packet switching
This is done by supplying various addressed packets, which are interconnected to have the conversation. New dedicated paths are created for sending the data. From the multiple paths to the destination, any path can be used to send data. Cellular digital packet data was designed for optimal operation with an analogue cellular system, especially AMPS.
Short message service. Short message service is the most common packet service that is supported on digital cellular networks like GSM, IS-136, EDGE and PDC (packet data service). It is a store-and-forward/packet mode service that provides inter-working with the various applications and services within a fixednetwork. For message transfer between relevant network entities, control and signaling channels (instead of normal traffic channels) ar generally used for data transmission.
General packet radio service (GPRS). GPRS essentially represents add-on capabilities to the basic voice-optimised cellular network that nevertheless maintain the essential characteristics of radio-access technology.
Enhanced data rates for GSM evolution (EDGE). In order to enhance the data handling capabilities of 2G service, radio-access portion had to be modifed. This modifcation was evolved in Europe in the form of EDGE. EDGE also supports a link adaptation mechanism that selects the best combination of modulation and encoding schemes based on the timevarying link quality.
EDGE concept applies to both circuit-mode and packet-mode data and is sufficiently generic for appliction to other digital cellular systems. It works in the 200kHz bandwidth with one or more high-level modulation schemes and a range of efficient coding methods. Modulation schemes are offset QPSK and offset 16 QAM.
Spread spectrum
It is a special communication technique that purposefully uses much more RF bandwidth than necessary to transmit a signal. This helps in improving the signal-to-noise (S/N) ratio. The main advantages of this technique are secure communication and resistance to intentional jamming. There are 75 channels in the 2400-2483.3MHz band.
There are two methods of perform-ing spread spectrum:
Frequency hopping. This technique spreads the narrow-band signal as a function of time. The transmitted frequency is changed to a different pre-assigned channel several times per second (hopped). The order in which the pre-assigned channels are selected is ‘pseudo random.’ In other words, the channel order is seemingly random but actually repeats itself at a definedinterval. The specificorder in which frequencies are occupied is a function of code sequence and the rate of hopping from one frequency to another is a function of information rate.
Direct sequence. This technique spreads a signal by expanding the signal over a broadband portion of the radio band. It uses a locally generated pseudo noise (PN) code to encode digital data to be transmitted. The most practical all-digit version is direct sequence. Binary phase-shift keying is the simplest and most often used modulation technique.
One of the most important features of spread-spectrum signals is that these contain a large number of very different signaling formats, used for communicating data symbols. It means that the receiver which detects one of these formats cannot detect any other format within a single message. The number of formats used in a spread-spectrum system is called multiplicity factor of the communication link and amounts to thousands.
CDMA. CDMA is a form of direct-sequence spread-spectrum technology that allows many users to occupy the same time and frequency allocations in a given band/space. CDMA assigns each user a unique spreading code to spread the baseband data before transmission, in order to help differentiate signals from various users in the same spectrum. It is the platform on which 2G and advanced 3G services are built.
After speech, the codec converts voice into digital signal. CDMA spreads the voice stream over the full 1.25MHz bandwidth of the CDMA channel, coding each stream separately. The receiver uses a correlator to despread the wanted signal, which is passed through a bandpass filter.Unwanted signals are not despread and not passed through the filter.
The rate of the spreading signal is known as the ‘chip rate’ as each bit in the spreading signal is known as ‘chip.’ All 2G networks support only single-user data rates of the order of 10 kbps, which is too slow for rapid e-mail and Internet browsing.
CDMA provides more than ten times the capacity of the analogue AMPS and fivetimes the calling capacity of GSM and TDMA systems. It requires fewer cell sites than GSM and TDMA.
Personal communication system
Personal communication system (PCS) is a new class of cellular telephone system such as AMPS. PCS systems are a combination of cellular telephone network and intelligent network, which is the entity of super-simple transfer (SST) inter-office protocol tha distinguishes physical components of the switching network such as signal service point, signal control point and signal transfer point from the services provided by SST network.
In essence, PCS is the North American implementation of European GSM standard. GSM utilised its own TDMA access methods and provided expanded capacity and unique services such as caller ID, call forwarding and short messaging. A critical feature was seamless roaming, which allowed subscribers to move across provider boundaries. The effort was directed towards second-generation cellular systems.
In 1990, a second frequency band was specified. This band included twodomains—1710-1785 MHz and 1805-1880 MHz, i.e., twice 75 MHz; three times as much as the primary 900MHz band.
Digital enhanced cordless telecommunication (DECT). DECT is a type of PCS system. DECT standard was developed by European Telecommunication Standards Institute (ETSI) for wireless PABX data LAN applications that represent closed environments requiring minimal open cordless access, since it was essential that products from different vendors not only coexist but interwork with each other.
DECT system has a TDMA/TDD frame structure with 24 slots that are equally allocated for downlink and uplink operation. DECT specifiesboth simplex (half-slots) and duplex (full slot) operation. Higher data rates are achieved by utilising multilevel modulation. The basic modulation scheme is a two-level Gaussian filled frequency-shif keying (GFSK), which is supplemented with 8-level modulation scheme leading to as high as 2.88 Mbps per carrier.
GSM
Global system for mobile communications (GSM) was developed by the Groupe Special Mobile, which was an initiative of the Conference of European Post and Telecommunications (CEPT) administrations. GSM was firs devised as a cellular system in a specific 900MHz band called the primary band. This primary band includes two sub-bands of 25 MHz each, 890-915 MHz and 935-960 Mhz.
GSM systems like Iridium, Globalstar and ICO use constellations of low-earth orbit (LEO) or medium-earth orbit (MEO) satellites and operate as overlay networks for existing cellular and PCS networks. Using dual-mode, these extend the coverage to any and all locations on the earth’s surface.
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Personal communication satellite service (PCSS) uses LEO satellite repeaters incorporating QPSK modulation and both FDMA and TDMA.
The main advantages of GSM are international roaming (in harmony with ISDN principles assuring inter-working between ISDN and GSM) and features like privacy and encryption, frequency hopping, discontinuous transmission and short message service. Other facilities include call forwarding, barring, waiting, hold and teleconferencing.
The basic architecture comprises a network sub-system, base station sub-system, mobile stations, and system interworking and interfaces.
A subscriber identity module (SIM) is required to activate and operate a GSM terminal. The SIM may be contained within the mobile station or it may be a removable unit that can be inserted by the user in his mobile set.
New developments along the way
Before we proceed to evolution from 1G to 4G, let me touch upon the new developments that took place in 1G to 4G.
Global positioning system (GPS). GPS is a reliable navigational aid available anywhere on the earth, operating in all weather conditions 24 hours a day. It can be used by marine, airborne and land users. GPS technology was developed in 1983.
GPS consists of three segments:
Space segment. GPS consists of 24 NAVSTAR satellites along with three spare satellites orbiting at 20,200 km above the earth’s surface in six circular orbital planes with a 12-hour orbital period each. These satellites operate at L1 band (1.575 GHz) continuously broadcasting navigational signals called coarse acquisition code. These codes can be received by anyone for decoding and findingnavigational parameters like longitude, latitude, velocity and time.
Control segment. It consists of a master control station (MCS) and a number of smaller earth stations called monitoring stations located at different places in the world. Monitoring stations track satellites and pass on the measured data to the MCS. The MCS computes satellite parameters (called ephemeris) and sends them back to the satellite, which, in turn, broadcasts to all GPS receivers.
User segment. The user segment consists of all moving and stationary objects with GPS receivers. A GPS receiver is a multi-channel satellite receiver that computes every second its own location and velocity.
Bluetooth. Compared to WLAN technologies, Bluetooth technology aims at so-called ad-hoc piconets, which are local-area networks with a very limited coverage and without the need for an infrastructure. The term ‘piconet’ is a collection of Bluetooth devices that are synchronised to the same hopping sequence. One device in the piconet can act as master and all other devices connected to the master act as slaves. The master determines the hopping pattern and the slaves have to synchronise to this pattern. The hopping pattern is determined by the device ID—a 48-bit worldwide unique identifier.The phase in the hopping pattern is determined by the master’s clock. All active devices are assigned a 3-bit active member address.
All parked devices use an 8-bit parked member address. Devices in standby mode do not need an address. The goal for Bluetooth development was to use a single-chip, low-cost, radio-based wireless network technology for laptops, notebooks, headsets, etc.
Bluetooth operates in the 2.4GHz ISM band. However, MAC, physical layer and the offered services are completely different. Bluetooth transceivers use Gaussian FSK for modulation and are available in three power classes: Class 1 (max. power 100 mW), class 2 (max. power 2.5 mW) and class 3 (max. power 1 mW).
Journey from 1G to 4G
1G system. 1G specifications were released in 1990 to be used in GSM. 1G systems are analogue systems such as AMPS that use FDM to divide the bandwidth into specificfrequencies that are assigned to individual calls.
2G system. These second-generation mobile systems are digital and use either TDMA or CDMA method. Digital cellular systems use digital modulation and have several advantages over analogue systems, including better utilisation of bandwidth, more privacy, and incorporation of error detection and correction.
2.5G system. It was introduced mainly to add latest bandwidth technology to the existing 2G generation. It supports higher-data-rate transmission for Web browsing and also supports a new browsing format language called wireless application protocol (WAP). The different upgrade paths include high-speed circuit-switched data (HSCSD), GPRS and EDGE.
HSCSD increases the available application data rate to 14.4 kbps as compared to 9.6 kbps of GSM. By using four consecutive time slots, HSCSD is able to provide a raw transmission rate of up to 57.6 kbps to individual users.
GPRS supports multi-user network sharing of individual radio channels and time slots. Thus GPRS supports many more users than HSCSD but in a bursty manner. When all the eight time slots of a GSM radio channel are dedicated to GPRS, an individual can achieve as much as 171.2 kbps. But this has not brought any new evolution.
EDGE introduces a new digital modulation format called 8-PSK (octal phase-shift keying). It allows nine different air interface formats, known as multiple modulation and coding schemes, with varying degree of error control and protection. These formats are automatically and rapidly selectable. Of course, the covering range is smaller in EDGE than in HSCSD or GRPS.
3G system. To overcome the short-comings of 2G and 2.5G, 3G has been developed. It uses a wideband wireless network that offers increased clarity in conversations. Countries throughout the world are currently determining new radio spectrum bands to accommodate 3G networks. ITU has established 2500-2690MHz, 1700-1855MHz and 806-960MHz bands. Here the target data rate is 2 Mbps. The data is sent through packet switching. Voice calls are interpreted through circuit switching.
3G W-CDMA (UMTS). Universal Mobile Telecommunication System (UMTS) or W-CDMA assures backward compatibility with 2G and 2.5G TDMA technologies. W-CDMA, which is an air interface standard, has been designed for always-on packet-based wireless service, so that computers and entertainment devices may all share the same wireless network and connect to the Internet anytime, anywhere.
W-CDMA supports data rates of up to 2.048 Mbps if the user is stationary, thereby allowing high-quality data, multimedia, streaming audio, streaming video and broadcast type services to consumers. With W-CDMA, data rates from as low as 8 kbps to as high as 2 Mbps can be carried simultaneously on a single W-CDMA 5MHz radio channel, with each channel supporting between 100 and 350 simultaneous voice calls at once, depending on antenna sectoring, propagation conditions, user velocity and antenna polarisation.
Time slots in W-CDMA are not used for user separation but to support periodic functions. (This is in contrast to GSM where time slots are used to separate users). The bandwidth per W-CDMA channel is 4.4 to 5 MHz.
Since the global standard was diffiult to evolve, three operating modes have been specified:A 3G device will be a personal, mobile, multimedia communication device (e.g., TV provider redirects a TV channel directly to the subscriber’s phone where it can be watched). Second, it will support video conferencing, i.e., subscribers can see as well as talk to each other. Third, it will also support location-based services, where a service provider sends localised weather or trafficconditions to the phone or the phone allows the subscriber to findnearby businesses or friends.
3.5G. It supports a higher through-put and speed at packet data rates of 14.4 Mbps, supporting higher data needs of consumers.
4G system. It offers additional features such as IP telephony, ultrabroadband Internet access, gaming services and HDTV streamed multimedia. Flash-OFDM, the 802.16e mobile version of WiMax (also known as WiBro in South Korea), can support cellular peak data rates of approx. 100 Mbps for high-mobility communications such as mobile access and up to 1 Gbps for low-mobility communications such as nomadic/local wireless access, using scalable bandwidths of up to 40 MHz. The infrastructure for 4G is only packet-based (all-IP).
Source : Mobile Communication: From 1G to 4G
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