10 Gbps Li-Fi system shows wireless data transfer in a new light

LiFi is a wireless optical networking technology that uses light-emitting diodes (LEDs) for data transmission.

LiFi is designed to use LED light bulbs similar to those currently in use in many energy-conscious homes and offices. However, LiFi bulbs are outfitted with a chip that modulates the light imperceptibly for optical data transmission. LiFi data is transmitted by the LED bulbs and received by photoreceptors.

LiFi's early developmental models were capable of 150 megabits-per-second (Mbps). Some commercial kits enabling that speed have been released. In the lab, with stronger LEDs and different technology, researchers have enabled 10 gigabits-per-second (Gbps), which is faster than 802.11ad. 

Benefits of LiFi:

• Higher speeds than Wi-Fi.
• 10000 times the frequency spectrum of radio.
• More secure because data cannot be intercepted without a clear line of sight.
• Prevents piggybacking.
• Eliminates neighboring network interference.
• Unimpeded by radio interference.
• Does not create interference in sensitive electronics, making it better for use in environments like hospitals and aircraft.

By using LiFi in all the lights in and around a building, the technology could enable greater area of coverage than a single WiFi router. Drawbacks to the technology include the need for a clear line of sight, difficulties with mobility and the requirement that lights stay on for operation.

Light might be the preferred option for transmitting data over long distances via cables, but when it comes to short range wireless, radio waves rule in the form of Wi-Fi and Bluetooth. Now Mexican company Sisoft, working with researchers from the Autonomous Technological Institute of Mexico (ITAM), has developed a wireless technology that transmits data in visible light emitted from LED lamps, while lighting the room at the same time.

Called Li-Fi, which is short for light fidelity, the technology is what is known as Visible Light Communication (VLC). Unlike infrared-based systems, VLC involves transmitting data using light visible to the human eye. In this case it is transmitted as intermittent, imperceptible flickers of light emitted by LEDs.

The team started out with audio, cabling up a protoboard table to a smartphone via its 3.5 mm audio jack. The protoboard table converted the audio signal into an optical signal that is transmitted by a special emitter across the spectrum of light generated by an LED lamp. At the receiving end, a receptor located in a speaker captured the signal and converted it back into an audio signal that was played by the speaker.

For wireless internet transmission, the principle is the same but makes use of a receptor device designed to be placed above a router. The router incorporates an LED lamp to transmit data so anyone falling within the halo of light emitted by the LED will be in range. However, only those with a receptor/transmitter device will be able to send and receive the signal.

The Sisoft team says it has used the technology to transmit audio, video and internet at rates of up to 10 gigabits per second. This is an improvement over similar Li-Fi systems developed at Siemens and Pennsylvania State University that achieved transfer rates of 500 Mbps and 1.6 Gbps, respectively.

In addition to its impressive transfer rate, Sisoft also highlights other benefits of the technology. Since the data is transferred via light, there is no way to hack it, making it safer, (although no mention is made of how easy it would be to take a peek at the data someone else is receiving). Additionally, it could be used in areas such as hospitals where radiation equipment can block or disrupt wireless signals. And of course, it provides illumination at the same time.

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Comparison Sony Xperia Z3 + Z3 Compact versus Z2 + Z1 Compact

Sony Xperia Z3 and Xperia Z3 Compact are upon us, with both devices now available in parts of Europe, and at least one of them likely to hit American shores next month. Sony's rapid-fire release cycle for high-end Android phones results in each generation of phones being the sum of many iterative updates upon the last. That's true of the Z3 series — both phones take their predecessors, the Xperia Z2and Xperia Z1 Compact, and improve upon them in ways both subtle and substantial.

We'll have more to say on both new Sony phones in the next week, but for now we've rounded up both phones and their forebears for a quick photo shoot. Check it out down below.

From right to left: Xperia Z1 Compact, Z2, Z3, Z3 Compact.

Xperia Z3 (top), Xperia Z2 (bottom). Sony evolves its "Omnibalance" design language with rounder metal edges on the full-sized Z3.

Top to bottom: Z3 Compact, Z1 Compact, Z3, Z2. The Z3 Compact uses a plastic frame in place of the Z1 Compact's metal, but the move from a cheap-feeling plastic back to glass means the newer Compact feels like the more premium device.

Clockwise from left: Z3, Z2, Z3 Compact, Z1 Compact. The Z3 is slightly narrower than the Z2, in addition to being thinner and lighter. The Z3 Compact is also thinner than its predecessor, while maintaining the same footprint with a larger 4.6-inch display (up from 4.3 inches).

Sony uses a 20.7-megapixel Exmor RS sensor across all four devices, though the Z3 series uses a slightly wider-angle lens.

Clockwise from top left: Z1 Compact, Z3 Compact, Z2, Z3.

From top: Z3 Compact, Z1 Compact, Z3, Z2. The buttons, ports and flaps are all in much the same location. The Z3 switches to thinner ports, though, while consolidating microSD and nanoSIM slots behind one door. (The flap on the left now houses the microUSB port alone.)

Xperia Z1 Compact (white) and Z3 Compact (black). The jump from a 4.3 to 4.6-inch display in the same device footprint results in narrower bezels.

Xperia Z3 + Z2. Despite the visual similarities, the Z3 feels substantially more comfortable in-hand, due to its rounded corners and more svelte chassis.

And finally, a redesigned (but just as fiddly) SIM tray for the Z3 and Z3 Compact, which use nanoSIMs. The older microSIM tray can be seen on the left.

SOURCE : androidcentral.com

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Qualcomm’s new high-end, 64-bit Snapdragon 808 and 810 to arrive soon

The company's first 20nm chips use ARM's Cortex A57 architecture.

Qualcomm

While most chip companies like to introduce new technologies into their high-end chips first and let them trickle down, Qualcomm has lately been taking the opposite approach with its Snapdragon chips. The company's first 64-bit chip with support for the new ARMv8 instruction set was the low-end Snapdragon 410, announced in December. At Mobile World Congress in February, Qualcomm announced the midrange Snapdragon 610 and 615. And today, the company is announcing the new Snapdragon 808 and 810, the two chips that will sit at the top of its lineup in 2015.

The Snapdragon 808 is the lower-end of the two chips. It combines two of ARM's high-end Cortex A57 GPUs with four low-end, low-power Cortex A53 GPUs in a big.LITTLE configuration—the big cores handle the heavy lifting while the smaller ones handle lighter tasks to conserve power. It includes an Adreno 418 GPU that will supposedly be about 20 percent faster than the Adreno 330 GPU in current Snapdragon 800 and 801 products.

The Snapdragon 810 will be the new flagship in the lineup, designed to support the upcoming 32-bitSnapdragon 805. It uses a total of eight CPU cores in a big.LITTLE configuration—four high-end Cortex A57 cores and four low-power Cortex A53 cores. Also included is a faster Adreno 430 GPU, which should be 30 percent faster and more power-efficient than the Adreno 420 GPU in the Snapdragon 805. Qualcomm's multitudinous model numbers make it a bit of a headache to compare the various Adreno GPUs directly, but you can work it out if you look at past releases: you'll get a 20 percent performance boost moving from the 330 to the 418 and a 40 percent boost moving from the 330 to the 420. If the 430 is 30 percent faster than that, some rough math suggests that the 430 will be around 82 percent faster than the 330.

Both the Snapdragon 808 and 810 will be built on a new 20nm manufacturing process, presumably from current manufacturing partner TSMC, and both will include new Qualcomm-designed Category 6 LTE modems. These modems will increase theoretical LTE download speeds to 300Mbps from the current Category 4 maximum of 150Mbps. Both also support 4K video output over HDMI as well as Bluetooth 4.1, NFC, and 802.11ac.

For the last two or so years, Qualcomm has steadily been moving away from using ARM's own architectures; most dual- and quad-core chips from the Snapdragon S4, Snapdragon 400, Snapdragon 600, and Snapdragon 800 families used the company's own custom "Krait" CPU architecture instead. With the Snapdragon 410, 610, and 810 families, Qualcomm's entire lineup for the end of 2014 and into 2015 will use ARM's Cortex CPU architectures instead. If we see a 64-bit, ARMv8 version of Krait, it's apparently not going to be this year.

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Types Of LED TV and Resolution

There has never been a better time to buy a new TV. Gone are the days when 32-inch TVs weighed 16 tonnes and cost £1,500. These days you can pick up a 50-inch LCD TV for closer to £300.

LCD panel technology has well and truly matured, and while brands like Sony and Panasonic push the boundaries of performance, you'll also find names like Toshiba doing very exciting things in the budget TV sector.

The practical upshot of this is that no matter what you're after, how big you want to go or how large your budget is, there's a perfect TV out there for you.

So which one is right for you, your family and your living space? In this buying guide, we will walk you through everything you need to know about being a new TV.

What types of TV are out there?

TV Guide

14 tips for getting the best picture quality out of your TV

There are a lot of different screen types out there, all working in different ways to produce the same results. Each technology has its own unique strengths and weaknesses so here are some basics to consider:

LCD TV: CCFL
Until recently, all LCD TVs were backlit by always-on, CCFL (cold cathode fluorescent) lamps. This ageing technology has been superseded by the superior LED method on more expensive sets, but is still standard on some cheaper models.

LED TV: Direct LED
These displays are backlit by an array of LEDs (light emitting diodes) directly behind the screen. This enables localised dimming – meaning immediately adjacent areas of brightness and darkness can be displayed more effectively – and greatly improves contrast. LED TVs are also more power efficient and capable of a wider colour gamut than CCFL sets.

LED TV: Edge LED
The LEDs of the backlight are mounted along the edges of the panel. This arrangement enables radically slender displays and offers superior contrast levels to CCFL, but can't achieve the same picture quality as directly lit LED sets. However, they do come in far cheaper which is why most LED TVs out there now use this technology.

OLED TV
The backlighting on OLED (organic light emitting diode) sets is achieved by passing an electric current through an emissive, electroluminescent film. This technique produces far better colours and higher contrast and also enables screens to be extremely thin and flexible. This is the holy grail display technology and only in 2014 did a bigscreen OLED TV go on sale. So it's brand new, it's expensive and the top brands are still struggling to get their heads around it.

Plasma TV
PDP (plasma display panel) TVs use glass panels containing millions of tiny cells filled with a mixture of inert gases. Electricity excites the gases, causing them to illuminate the pixels across the screen. Plasma, while arguably superior to LCD in terms of contrast and colour accuracy, is only viable on large (42in+) screens and has been dropped by all but a handful of manufacturers.

Curved TV
Some manufacturers are now making TVs that have slightly curved screens. But unlike old CRT TVs, the curve is inwards rather than outwards. The idea is that this makes every pixel equidistant from your eyes, delivering a more satisfying picture. However, there are drawbacks for this type of screen - the main one being that if you sit far enough to one side – more than 40 degrees or so – the curve clearly starts to affect the image's geometry, foreshortening content near to you and compressing the image's centre.

What resolution should I go for?

HD
HD TVs come in two resolutions. Sets with the HD ready badge meet the requirements set by the European Information and Communications Technology Industry Association (EICTA). These criteria include at least one HDMI port and component video inputs as well as a resolution of at least 1,024 x 768-pixels. Meanwhile, full HD TVs have a higher resolution of 1,920 x 1,080 pixels.

Ultra HD and 4KThe resolution of Ultra HD is exactly four times higher than full HD - 3840 x 2160. It means a far more detailed picture, with content requiring a lot more bandwidth and storage space. 4K TVs tend to be good at upscaling HD video to Ultra HD but there are currently very few options for watching native 4K content.

What kind of tuner do I need?

TVs in the UK come with two types of tuner: DVB-T2 (Freeview HD) and DVB-S (Freesat HD). Some TVs such as many sets from Panasonic have both tuners onboard, but most do not. So which should you go for?

Freeview HD
Freeview is the natural successor to the analogue TV signal of old, flying the flag for free-to-air TV through a traditional aerial. So your decision of which tuner to go for could well be decided according to what receiving devices you've already got strapped to your roof. If you've got a traditional TV aerial only, Freeview is the obvious option. Equally, if you're buying a TV for a second room, you might have to rely on a portable aerial which again would make Freeview your best bet.

Freesat HD
Freesat is similar to Freeview in that it's free-to-air, but different in that it's delivered through a satellite dish. Freesat uses the same satellite as Sky HD - the Astra/Eutelsat satellite which sits in the sky at 28.2E. That means if you've got a Sky dish, you can easily plug a Freesat TV or box in without having to move it. Freesat HD is ideal for large living room TVs as it delivers slightly higher quality pictures than Freeview, has fewer problems with signal, and also has a much larger selection of channels both in standard definition and high definition. It'll also likely be the first to carry 4K TV channels when they eventually launch.

What does TechRadar recommend?

Best 32-inch TVs

The perfect size for bedroom TVs or sets for smaller rooms

Most living rooms can't physically take a TV much bigger than 32-inch, making this size by far the best for a lot of people in the UK. But within this size division, there's plenty of choice. A basic HD-ready set can be found for less than £300 is you search hard, though it's just as easy to spend over £2k on the best ones. There's only one certainty at this size – your new TV will be a LCD TV. If you're lucky it could have LED backlighting, but it won't be a plasma; LG used to make plasmas at this size, but there's not one on sale currently. 10 best 32-inch TVs in the world today

Best 40 and 42-inch TVs

The sweet spot for plasma TVs offers lots of bang for your buck

Once known simply as 'plasma screens' in the collective consciousness, the 40-42-inch size is where the flatscreen dream started in the late 1990s - and where it's still at its most innovative and best. Now a lot more varied, with plasmas rubbing shoulders with (and quickly being outnumbered by) LCD TVs and their ultra-modern LED TV makeover, 40-42 inches is still the sweetspot for anyone not overly concerned with ruining the interior design of their living room. As well as being the fastest growing sector of the market, this size also offers possibly the best value TVs around. Serious home cinema addicts have moved on to 50-inch and bigger screens, leaving this category a swarm of slashed prices. 10 best 40 and 42-inch TVs

Best 46 and 47-inch TVs

Offering the pinnacle of performance, this is where it gets serious

There was a time when plasma screens reigned supreme in the 46-inch TV market. But in much the same way as a meteor strike killed off the dinosaurs, the second coming of the LCD TV is the invasive species that has done for plasma. We're still huge advocates of plasma on TechRadar, don't get us wrong, but the tech is dying out at this size. Old-school CCFL tech has been replaced by LED backlight scanning and technical wizardry to make LCD tech viable in large sizes. So the majority of TVs in this size bracket are now from the LED side of the wall, and that's not necessarily a bad thing. LED TVs these days are brighter than plasmas, they're thinner and there's a lot more variety on show. So here's our selection of the best 46-inch, 47-inch and now also 48-inch TVs for your perusal.. 10 best 46, 47 and 48-inch TVs

Best 50 and 55-inch TVs

Where the home cinema experience begins

The size where a home cinema turns from dream to reality, it's also at this 50-55-inch TV screen size that 3D starts to become immersive enough to convince and impress. This size, last year dominated by full HD models, is now being overrun by Ultra HD 4K models. While LED tech has gone a long way towards condemning plasma to a role on the outskirts of the TV industry, at 50-inches and above, plasma really comes into its own if you can find one. Most home cinema buffs still swear by plasma, with its cinematic colours and deep blacks making for a real movie-watcher's paradise. But 2014 sees the first batch of 50-inch LED-backlit panels off the production line, a development that further marginalises plasma technology at one of the sizes it previously dominated. If you're looking for a dream movie-watching experience, check out these home cinema beauties. 10 best 50 and 55-inch TVs

Best 60-inch TVs and above

If you want the best, you'll need to pay the best

If you're feeling extravagant or want to furnish your big living room with a similarly big TV, 60 inches or more of television will certainly make a statement. There are some truly massive TVs available these days, with Ultra HD-toting 84-inch screens such as the LG 84LM960V, Toshiba 84L9300, Sony KD-84X9005A and Samsung UE85S9ST. But for most of us, 65 inches of screen space is luxurious enough, while still being manageable. Gone are the days when the over-60s were mere monitors; expect to find all the niceties a good living room-ready TV should have, such as Freeview HD tuners, perhaps even Freesat HD tuners, too, plus smart TV apps and 3D compatibility. There's a smattering of plasmas here - it's the size category where the original flatscreen TV tech truly excels. But as plasma fades, the real story in this category is the rise of the 4K LCD. So what's the best 60-65-inch TV for you? 10 best 60 and 65-inch TVs in the world today

Best 4K Ultra HD TVs

The latest big thing in big screens

Everyone wants an Ultra HD 4K TV! Yes, okay, we all know there isn't much 4K source material to properly showcase the stunning picture quality, but Netflix has at least started to offer 4K content. There could also still be a 4K Blu-ray format later this year, and before you know it there'll be test transmissions and perhaps even a 4K TV channel from Sky or the BBC. It's all about future-proofing, though there's slightly more to it than that; some of the first batch of Ultra HD TVs pump out best-ever Blu-ray images, thanks to some wonderfully adept upscaling tech. The birth of 4K could also lead to the re-birth of 3D – it just looks so much better at this higher resolution. The big stumbling block – as always – is money, but already there are relative bargains to be had and, better still, some sumptuous designs stuffed with new innovations. The race for 3840x2160 pixels is on. 10 best 4K TVs in the world today

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