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By Dexter Johnson

NanoclastSemiconductorsMaterials
Nanostructured Device Purifies Water With Light

By Dexter Johnson
Posted 16 Aug 2016 | 20:00 GMT
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 A nanostructured molybdenum disulfide device can purify a water sample 50 times as fast as UV-only devices.
Image: C. Liu/Nature Nanotechnology
The combination of nanomaterials with water has produced some intriguing possibilities—among them, powering turbines by taking advantage of the production of steam from water that is near freezing, splitting a water molecule through artificial photosynthesis to produce hydrogen gas, dramatically improving water desalination processes, and purifying microbe-infested water simply and cheaply.

Now, researchers at the U.S. Department of Energy's SLAC National Accelerator Laboratory and Stanford University have added a new solution to water purification: a nanomaterial that can reportedly kill 99.999 percent of bacteria in water within just 20 minutes—a process that would otherwise take up to two days if only the ultraviolet (UV) light from the sun were used as a disinfectant.

In research described in the journal Nature Nanotechnology, the scientists successfully aligned molybdenum disulfide films vertically on the surface of glass so that the pane was able to make use of the full visible solar spectrum. These walls of molybdenum disulfide form a kind of maze on the glass and appear like fingerprints on the glass. This device, which is about half the size of a postage stamp, is able to absorb 50 percent of the sun’s energy by utilizing the full spectrum of visible light—a huge leap beyond the capabilities of UV-only devices.

The two-dimensional version of molybdenum disulfide employed by the researchers has been gaining the interest of researchers for its solar absorption capabilities over the past few years. What the researchers from SLAC and Stanford have done is place a thin layer of copper on top of MoS2 walls to yield a photocatalyst that is triggered when sunlight hits the walls. This catalyst stirs a chemical reaction that produces bacteria-killing “reactive oxygen species” such as hydrogen peroxide.

While the researchers concede that the material cannot address all pollutants in water (it won’t flush out chemical pollutants), they have shown that it can kill three different strains of bacteria.

http://bit.ly/2brXEV0

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According to Google Scholar, more than 5,000 scientific papers that discuss OAM were published in 2015. Communications is a powerful property of OAM.

Overlapping beams with different values of OAM essentially behave as if they can’t “see” each other. To use the parlance of communications engineers and physicists, those OAM beams are orthogonal to one another. This means that each beam is distinct. It can’t be constructed using beams with other values of OAM, and it isn’t intrinsically capable of interacting with those other beams.

This orthogonality means that OAM beams can occupy the same space without interfering with one another. In fact it’s theoretically possible to use an infinite number of beams, each with a different value of OAM, to carry signals. In practice, there are limitations, as there always are.

A major step forward for OAM communications occurred in 2004, when physicist Miles Padgett and his colleagues showed that OAM waves could be used to encode data, by using different values of OAM to represent information. Later, it became clear that a beam with a single fixed OAM value could act as a data channel—that is, it could be modulated in a variety of conventional ways to carry information. The most straightforward of such modulation methods is on-off keying, which uses the presence and absence of a beam to represent “1” and “0” data bits.

There are a variety of ways to create and transmit helical beams.The transmitter generates regular laser beams, which are then passed through a spatial light modulator, based on liquid crystal, in order to impart a twist to the beam. At the receiving end, each OAM beam was converted back into a regular plane wave by passing it through a spatial modulator with the inverse pattern. The data could then be recovered by a conventional optical receiver.

In 2012, the author published the first journal article on this approach. Our experiment sent 32 different optical beams of the same frequency, each carrying 80 gigabits per second of data, over a modest distance—just 1 meter—in the laboratory. But the total transmission rate, some 2.5 terabits per second, was actually quite high for free-space communications. And it held out the promise for longer-distance transmissions and, because we used only one frequency, much higher data rates.

The research can be roughly divided into three fields: free-space optical links, traditional radio-frequency wireless transmissions, and fiber-optic communications.

The first two, free-space optical and radio, are the farthest along. In the optical category, in 2014, Anton Zeilinger of the University of Vienna and colleagues reported that they had used OAM light to send data, including a grayscale image of Mozart, between two sites in Vienna separated by 3 kilometers.

Quantum communication, which can be used to send information far more securely than traditional systems do, can also take advantage of OAM. Today quantum bits, or qubits, can be made of photons that are constructed from a superposition of two possible polarization states—vertical and horizontal. But OAM isn’t just a property of electromagnetic waves; it’s also a quantum property of single photons. A single photon can have many possible values of OAM, which can be used to increase the capacity of a quantum link. Robert Boyd of the University of Rochester, in New York, has demonstrated quantum communication systems that can carry more than one bit per photon by using OAM.

About the Author
Alan E. Willner is a professor of electrical engineering at the University of Southern California.

http://bit.ly/2bLRHGD

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A remarkable invention about light: Certain beams, traveling through space with a spiraling pattern suggestive of a corkscrew, carry a form of momentum called orbital angular momentum.

OAM waves with different “twists” don’t interfere with one another. That means they can be overlaid one on top of another to carry a theoretically unlimited number of different data streams at the same time. Hardware that can transmit and receive even a few such OAM beams could dramatically boost the capacity of optical and radio transmissions without placing any more demands on the crowded electromagnetic spectrum than we do today.

One of the most curious aspects of light is that it has energy and momentum, just like an ordinary physical object moving through space, even though it doesn’t have mass. And just like an ordinary physical object, when light strikes something, it exerts a force. A solar sail, for example, takes advantage of this property as it accelerates through space, pushed by sunlight alone. Light carries that “pushing” capacity—its linear momentum—along the direction it’s moving. But light can also have angular momentum.

For a long time, the only commonly discussed form of such momentum was spin angular momentum. To understand how it works requires a bit of background on polarization. A ray of light has an electric field associated with it that oscillates perpendicularly to the direction of the ray. In light that is linearly polarized, the electric field oscillates along a fixed line. Light that is circularly polarized has an oscillating electric field that rotates around the direction the light moves in. Such circularly polarized waves have spin angular momentum, the electromagnetic equivalent of a spinning top or a planet rotating on its axis. Remarkably, this form of momentum can also impart a torque: Shine light with spin angular momentum on a microscopic object and you can make it rotate.

Not all light has OAM. To have it, a beam must have a particular kind of phase front. Phase is the component of an electromagnetic wave that governs the arrival times of its peaks and troughs.

Consider a beam of light --the beam as a collection of a very large number of “miniwaves.” But there is no rule demanding that different parts of a light beam all have the same phase. In the case of a helical wave, the sort that carries OAM, the miniwaves in the cross section of the beam aren’t uniform. Instead, the phase of each miniwave depends on its angular location around the center of the beam.

To give a more intuitive feel for how this translates into a “twisting” beam, think of those miniwaves as they move through space. At first, all the miniwaves that are at their peak will lie along some angle, like the hand on a clock. A short time later, those miniwaves will no longer be at their peak; instead, the peak will have advanced, like the clock hand, to another set of miniwaves at another angle around the circle. This process continues, so that if you track the angular location of the miniwave peaks, the wave appears to twist as it moves.

But the exploitation of OAM may have the biggest impact in field of communications. OAM waves with different “twists” don’t interfere with one another. That means they can be overlaid one on top of another to carry a theoretically unlimited number of different data streams at the same time. Hardware that can transmit and receive even a few such OAM beams could dramatically boost the capacity of optical and radio transmissions without placing any more demands on the crowded electromagnetic spectrum than we do today. Indeed, my team at the University of Southern California, in Los Angeles, and others have performed experiments to test this idea, and they worked just as the theory predicted.

If OAM communications sounds familiar, you may have noticed the news a few years ago when one of the first OAM radio demonstrations was performed. At the time, some engineers argued that the approach wasn’t new and was instead just a version of another strategy for sending multiple waves at the same time. But since then, it’s become clear that OAM transmission really is a novel and powerful technology, one that could allow us to transmit much more information along wireless connections and dramatically speed up parts of the networks that underpin the Internet. The technological challenge is finding good ways to harness OAM. We are finally starting to do just that.

Fig. 1

One of the most curious aspects of light is that it has energy and momentum, just like an ordinary physical object moving through space, even though it doesn’t have mass. And just like an ordinary physical object, when light strikes something, it exerts a force. A solar sail, for example, takes advantage of this property as it accelerates through space, pushed by sunlight alone. Light carries that “pushing” capacity—its linear momentum—along the direction it’s moving. But light can also have angular momentum.

For a long time, the only commonly discussed form of such momentum was spin angular momentum. To understand how it works requires a bit of background on polarization. A ray of light has an electric field associated with it that oscillates perpendicularly to the direction of the ray. In light that is linearly polarized, the electric field oscillates along a fixed line. Light that is circularly polarized has an oscillating electric field that rotates around the direction the light moves in. Such circularly polarized waves have spin angular momentum, the electromagnetic equivalent of a spinning top or a planet rotating on its axis. Remarkably, this form of momentum can also impart a torque: Shine light with spin angular momentum on a microscopic object and you can make it rotate.

In 1992, physicist Les Allen, working with Han Woerdman and colleagues at Leiden University, in the Netherlands, pointed out that a certain spiraling beam carries another form of angular momentum—orbital angular momentum. If light with spin angular momentum is like a spinning planet, the physical analogue of OAM light could be a planet orbiting the sun. OAM light can also impart a torque, a “twist” that, depending on where the beam hits, can cause a small object to rotate or move in an orbit around the center of the beam.

Not all light has OAM. To have it, a beam must have a particular kind of phase front. Phase is the component of an electromagnetic wave that governs the arrival times of its peaks and troughs. To picture what a phase front looks like, consider a beam of light. If you look at its cross section, it’s easy to view the beam as a collection of a very large number of “miniwaves.” If all these miniwaves oscillate in unison as they propagate—as they do in a common laser beam—the beam is a plane wave, and it has a flat phase front. At any given point along the beam’s propagating direction, the entire cross section has one phase value—that is, all the minibeams are at the peak of a crest, the bottom of a trough, or more likely, somewhere in between.

But there is no rule demanding that different parts of a light beam all have the same phase. In the case of a helical wave, the sort that carries OAM, the miniwaves in the cross section of the beam aren’t uniform. Instead, the phase of each miniwave depends on its angular location around the center of the beam. If you were to trace a circle around the center, the phase would either steadily increase or decrease as you go around.

A plane wave, such as an ordinary laser beam, has the same phase at each point in cross section; the value, which corresponds to where each miniwave in the beam is in its oscillation, changes as the beam propagates. In an OAM beam, the phase can take on a variety of values, and the resulting phase profile rotates around the center of the beam as it moves.       

To give a more intuitive feel for how this translates into a “twisting” beam, think of those miniwaves as they move through space. At first, all the miniwaves that are at their peak will lie along some angle, like the hand on a clock. A short time later, those miniwaves will no longer be at their peak; instead, the peak will have advanced, like the clock hand, to another set of miniwaves at another angle around the circle. This process continues, so that if you track the angular location of the miniwave peaks, the wave appears to twist as it moves. To get a better sense of how this phase behavior translates into what looks like movement, consider a neon sign with individual bulbs timed to turn on and off in sequence. With the right program, the neon light can look as if it’s moving in one direction, even though none of the bulbs move. The same is true for OAM. Each miniwave in a beam oscillates steadily, but the time sequence at which each miniwave peaks makes the phase front twist, describing a helix as the beam moves.

Crucially, the more dramatic the phase shift as you move in a circle around the cross section of the beam, the bigger the twist and the higher the amount of OAM. Phase changes around the entire circle can come in integer multiples of 360 degrees.

Fig. 2.

Such a twisting, helical wave is hard to visualize, but it does produce a clear visible effect. Unlike a conventional beam, which is brightest at the center, the cross section of a helical beam has a ringlike shape, with a dark center. This happens because the center of the beam is full of miniwaves with every possible phase, and a miniwave at its peak is very likely to overlap at least in part with a miniwave at its trough. The opposing pairs cancel one another out through destructive interference.


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Telecom Forum / 5 Myths about 5G (Part 2)
« on: May 31, 2016, 05:07:53 PM »
3. 5G will replace 4G

Another assumption that Onoe loves to challenge is that 5G networks will quickly render 4G obsolete. Not so, he says. The dominance of a new wireless network is more of an evolution than a sudden debut. "Of course this happens eventually but not overnight,” he says.

In this case, too, history is on his side. No wireless network has ever wholly replaced its predecessor, if only because there are so many areas of the world such as Bangladesh where 3G and even 2G service is still the norm.

4. 5G will require more spectrum

There’s an oft-repeated line in the wireless world: With more smartphone users consuming more bandwidth per user, the portion of spectrum dedicated to mobile data is getting crowded—and we need more of it! But Onoe maintains that carriers can find plenty of existing spectrum to support 5G and free up more through re-farming, or the recycling of that which is currently dedicated to other uses.

5. For 5G, everything will need something new

Many researchers and industry professionals are eager to find as many future uses for 5G as possible, and to enhance or expand existing services on the new network. Onoe insists that just because a new generation of wireless is in the works, it does not mean that it can or should serve every possible need under the sun—whether it’s autonomous driving, IoT, or mobile broadband service. “This is the most frustrating to me,” he says.

He admits to feeling a bit of déjà vu, with today’s hype reminding him of conversations about how 4G would suddenly enable new technologies and services. At the end of the day, says Onoe, 5G will eventually deliver on many of the promises that the industry has dreamt up—and possibly even a few others it has yet to consider. But it’s just too early, he says, for the industry to tout it as the path to so many potential futures.

Reference:

http://spectrum.ieee.org/tech-talk/telecom/wireless/5-myths-about-5g?utm_source=Tech+Alert&utm_medium=Email&utm_campaign=TechAlert_05262016&bt_email=apesnajnin@gmail.com&bt_ts=1464267752951

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Telecom Forum / 5 Myths about 5G (Part 1)
« on: May 31, 2016, 05:01:22 PM »
5G enthusiasts say the widely heralded future wireless network will deliver lightning-quick mobile data speeds with virtually unlimited capacity, blanket cities with high-quality Internet access, provide low bandwidth IoT connections to billions of devices, and even enable autonomous driving. But the industry has only just begun to set standards that will define 5G’s capabilities and launch very early trials that will establish its parameters.

Seizo Onoe, CTO of NTT DOCOMO, Japan’s largest mobile carrier, is traveling around to conferences trying to keep everyone’s expectations in check. “In the early 2000s, there was a concrete 4G technology but no one called it 4G,” Onoe laments. “Today, there are no contents of 5G but everyone talks about 5G, 5G, 5G.”

On Wednesday, Onoe presented a keynote at the IEEE International Conference on Communications in Kuala Lumpur, Malaysia. He sought to dispel some of the most pervasive myths about 5G. It was the second time in two months that he attempted to spread this message. In April, he gave the same talk to a group of industry professionals at the Brooklyn 5G Summit in New York City.

Here are a few of the falsehoods about 5G that Onoe is eager to debunk:

1. 5G will be a “hot spot” system

Many experts believe telecom operators will deploy 5G over so-called small cell networks. Unlike cell towers of the past that broadcast signals indiscriminately over a wide area, they envision new base stations being affixed to rooftops and lampposts to serve hyper-local areas. In theory, this design should provide better and faster coverage to those fortunate enough to live in said areas (mainly, cities in wealthy countries).

Onoe says this belief is an unfortunate self-fulfilling prophecy. By labeling 5G as a small cell or “hot spot” system at this stage, the industry is closing itself to other innovations. That’s a problem, he says, because such a “hot spot” system may not be so convenient to build in rural areas. Without a commercially viable strategy, the small cell structure of 5G could end up widening the digital divide.

Tech TalkTelecomWireless
5 Myths About 5G

By Amy Nordrum
Posted 25 May 2016 | 13:15 GMT
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Illustration: iStockphoto
Without a doubt, 5G is the hottest topic in wireless circles today. Many of the field’s most celebrated researchers and highest-paid executives are focused on forging this ultra-fast and high-bandwidth successor to 4G LTE. Among them, this opportunity to construct the next generation of wireless is often compared to Halley’s Comet: It comes around only once or twice in a person’s career. 

5G enthusiasts say the widely heralded future wireless network will deliver lightning-quick mobile data speeds with virtually unlimited capacity, blanket cities with high-quality Internet access, provide low bandwidth IoT connections to billions of devices, and even enable autonomous driving. But the industry has only just begun to set standards that will define 5G’s capabilities and launch very early trials that will establish its parameters.

But in many cases, the term “5G” is bandied about as a panacea that already exists. That’s why Seizo Onoe, CTO of NTT DOCOMO, Japan’s largest mobile carrier, is traveling around to conferences trying to keep everyone’s expectations in check. “In the early 2000s, there was a concrete 4G technology but no one called it 4G,” Onoe laments. “Today, there are no contents of 5G but everyone talks about 5G, 5G, 5G.”

At first glance, Onoe may seem like an unlikely messenger. If 5G lives up to the hype, the world’s mobile carriers stand to benefit most from the new demand and services it will create. On the other hand, Onoe’s industry ties also make it within his best interest to keep his collaborators grounded in reality so 5G can be deployed as quickly and successfully as possible. “I want to right the direction for where 5G is going,” he says.

On Wednesday, Onoe presented a keynote at the IEEE International Conference on Communications in Kuala Lumpur, Malaysia. He sought to dispel some of the most pervasive myths about 5G. It was the second time in two months that he attempted to spread this message. In April, he gave the same talk to a group of industry professionals at the Brooklyn 5G Summit in New York City.

Here are a few of the falsehoods about 5G that Onoe is eager to debunk:

1. 5G will be a “hot spot” system

Many experts believe telecom operators will deploy 5G over so-called small cell networks. Unlike cell towers of the past that broadcast signals indiscriminately over a wide area, they envision new base stations being affixed to rooftops and lampposts to serve hyper-local areas. In theory, this design should provide better and faster coverage to those fortunate enough to live in said areas (mainly, cities in wealthy countries).

Onoe says this belief is an unfortunate self-fulfilling prophecy. By labeling 5G as a small cell or “hot spot” system at this stage, the industry is closing itself to other innovations. That’s a problem, he says, because such a “hot spot” system may not be so convenient to build in rural areas. Without a commercially viable strategy, the small cell structure of 5G could end up widening the digital divide.

Onoe says it would be better to keep an open mind to other technologies that could someday bring 5G to rural customers—or leave room for brilliant business models that could perhaps justify building far-reaching networks comprised of small cells. “At this point, I don't believe we can achieve that,” he says. “But in the past, [the industry ultimately] realized what I thought was impossible.”

2. 5G will require substantial investment

One of the boldest statements in Onoe’s speech was that deploying 5G will not require a ton of investment. This is counterintuitive to anyone listening to predictions for widespread deployment of cutting-edge technologies from massive MIMO to millimeter wave, or projections for the number of base stations required to build out a small cell network.   

But rather than requiring a complete overhaul of existing networks as some imagine, Onoe believes 5G will be deployed largely on existing infrastructure. Better service, he insists, does not always correlate with greater capital expenditures. NTT DOCOMO’s 600 billion yen in capital expenditures last year marked a 15-year low, even as the data traffic across its networks grew 6300 percent since 2000.

(to be continued)

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নিজের বাচ্চাসহ কাজিনদের পড়ানোর সুবাদে স্কুলের এখনকার সিলেবাস কিছুটা হলেও দেখা হয়েছে। কন্টেন্ট যথেষ্ট সমৃদ্ধ! আমাদের সময়কার চেয়ে অনেক গুণ! ফেইসবুকে কিছু সেকুলারিজম বনাম ইসলামিক গল্প সাহিত্য নিয়ে আলোচনা - সমালোচনা দেখেছি, সেটা একটা দিক। কিন্তু এটা বাদ দিলে সাধারণ অর্থে জানার মতো বহু কিছুই আছে এখনকার সিলেবাসগুলোতে। এখন প্রশ্ন থেকে যাচ্ছে শিক্ষকদের পাঠদান পদ্ধতি এবং প্রশ্ন করার পদ্ধতির উপর।

ঠিক এই দুটো বিষয়কে কেন্দ্র করেই আমাদের বিশ্ববিদ্যালয়সহ অনেক বিশ্ববিদ্যালয়ে শিক্ষকদের নানারকম ট্রেনিং দেয়ানো হচ্ছে। আমাদের বিশ্ববিদ্যালয়ে প্রতি সেমিষ্টারেই নতুন জয়েন করা শিক্ষকদের এক সপ্তাহ ট্রেনিং দেয়ানো হয় কিভাবে ছাত্রদের ক্লাসে এনগেজড করতে হবে, মানে ইন্টারেকশনাল শিক্ষাপদ্ধতি (বাই লেটারেল), [ওয়ান ওয়ে নয়, মানে শিক্ষক কেবল বলবে, ছাত্ররা কেবল শুনবে, নোট নিবে এমন নয়]। ছাত্ররাও যেন একটা আপকামিং টপিকের উপর নিজেদের কিছু চিন্তাভাবনা শেয়ার করতে পারে সে সুযোগ তৈরী করে দিতে হবে, সাডেন কুইজ, পোলিং সিস্টেমের মাধ্যমে ছাত্ররা বিভিন্ন সমস্যার বা প্রশ্নের ব্যাপারে তাদের মতামত তুলে ধরবে ইত্যাদি ইত্যাদি... এর থেকেও আরো উন্নত ধারনা নিয়ে হাজির হয়েছে বিশ্বব্যাংক, IQAC (Internal Quality Assurance Cell) ট্রেনিং দেয়া হচ্ছে বিভিন্ন পাবলিক ও প্রাইভেট বিশ্ববিদ্যালয়ের শিক্ষকদেরকে। শেখানো হচ্ছে কিছু কি-ওয়ার্ড যা দিয়ে প্রশ্নের ধরণ ও কোয়ালিটি নির্ধারণ হবে, যা কিনা ভেরিফাই করা হবে ব্লুমস ট্যাক্সোনমি নামক একটা ছক দিয়ে, সাধারণত নিচের ক্লাসগুলোতে মুখস্থ বা বোঝা বা ব্যাখ্যা করা টাইপ প্রশ্ন বেশি হতে পারে আর উপরের ক্লাসের প্রশ্নতে বিশ্লেষণধর্মী, মাপকাঠি নির্ধারণ, নতুন কিছু চিন্তা করার মতো প্রশ্ন বেশি থাকবে। প্রতিদিনকার লেসন প্ল্যান তৈরীর পদ্ধতি যাতে থাকবে নির্দিষ্ট টপিকের উদ্দেশ্য, আউটকাম, ডিটেইলস টপিকের কোনটা কত সময় ধরে পড়ানো হবে, কি কি টুলস ব্যবহার করা হবে, কিভাবে তার এসেসমেন্ট হবে, মোদ্দাকথা ৯০ মিনিটের একেকটা ক্লাস একজন শিক্ষক কিভাবে দক্ষতার সাথে ছাত্রদের সমান বা অনেকটা একটিভ অংশগ্রহণ এর মাধ্যমে সম্পন্ন করবেন, সেটাই থাকবে এই লেসন প্ল্যানে। আর ২০-৩০টা লেসন প্ল্যান নিয়েই তৈরী হবে একটা কোর্স প্রোফাইল/ সিলেবাস। এরকম প্রায় ৪৮-৫০টা কোর্স প্রোফাইল/ সিলেবাস নিয়ে তৈরী হবে কারিকুলাম।




আবার কেবল সাবজেক্ট জ্ঞান নয়, পাশাপাশি একজন পূর্নাঙ্গ মানুষ হিসেবে বেড়ে ওঠার জন্য কারিকুলামে যুক্ত করা হয়েছে 'আর্ট অফ লিভিং' নামক কোর্স, যার মাধ্যমে ছাত্ররা তাদের জীবনধারা, চিন্তাধারা আমুল পরিবর্তন করে নিতে পারবে এবং অনেকেই এর মাধ্যমে উপকৃত হচ্ছে। কিভাবে কথা বলতে হয়, কিভাবে পরিবারের এবং পরিবারের বাইরের মানুষগুলোর সাথে আচরণ করতে হয়, দায়িত্ব পালন করতে হয়, কিভাবে একটা সোশাল গেদারিং এ আচরণ করতে হবে, একতা ইন্টারভিউ বা অফিসের বস এর সাথে ইন্টারেকশান কেমন হতে হবে -- এসব কিছুই শেখানো হচ্ছে এই কোর্সটিতে। এর পাশাপাশি টিম ওয়ার্ক গড়ে তোলার জন্য নানারকম ক্লাব একটিভিটিস, খেলাধূলা, বিতর্ক, সাংস্কৃতিক অনুষ্ঠান তো রইলো আগেকার মতো। সাথে যুক্ত হয়েছে সোশাল নেটওয়ার্কিং এ লেখালেখি, ফেইসবুক, ব্লগ, ফোরামে বিভিন্ন বিষয়ের উপর লেখালেখি করাটা রীতিমত শিক্ষকদের পারফরমেন্স উন্নতির মাপকাঠি হিসেবে দেখা হচ্ছে। গবেষণার জন্য ফান্ড এখনো অপ্রতুল হলেও দিনে দিনে ফান্ড বাড়ানো হচ্ছে।

নতুন করে আরেকটি কোর্সের প্রস্তাব নিয়ে এলো ভারতের তিনজন প্রফেসর। আমাদের মতো এই উপমহাদেশে ভারতেও শিক্ষার হার বেড়েছে, কিন্তু মূল্যবোধ কমেছে। এ নিয়ে সুপ্রীম কোর্টের এক রায় আমলে নিয়ে সেখানে শুরু হয়েছে ব্যাপক শিক্ষাব্যবস্থা সংস্কার। তারই একটি বড় অংশ হলো "হিউম্যান ভ্যালুস এবং প্রফেশনাল এথিকস" নিয়ে কাজ করা। প্রায় ৩৫টি বিশ্ববিদ্যালয়ে এই কোর্সটি চালু হয়েছে, বিভিন্ন জায়গায় ওয়ার্কশপ চলছে, ভুটান ও বাংলাদেশে এরই ধারাবাহিকতায় ওয়ার্কশপ হয়ে গেল। সেখানে শেখানো হচ্ছে প্রত্যেক মানুষের পটেনশিয়ালিটি আছে, সবাই সুখী হতে চায়। কাউকে দুঃখ দেয়াটা ইন্টেনশনাল বিষয় নয়, যোগ্যতার অভাবেই এমনতা হয়ে থাকে। সত্যিকার অর্থে কেউ কাউকে দুঃখ দিতে চায় না।

আমেরিকা বলি, বিশ্বব্যাংক বলি বা ভারত বলি, আর্ট অফ লিভিং বলি আর হিউম্যান ভ্যালুস বলি, প্রত্যেকটা ধর্মের বা নৈতিকতার মূল কথাই হলো নীতিবান হওয়া, বিনয়ী হওয়া, বিচক্ষণ হওয়া, প্রজ্ঞাবান হওয়া। ফাউন্ডেশন ডে উদযাপন উপলক্ষে আমার ডিপার্টমেন্ট আয়োজন করতে যাচ্ছে 'আর্ট লিভিং ইন ইসলাম' নামক সেমিনার। বিশ্ববিদ্যালয়গুলোর পাশাপাশি স্কুল কলেজগুলোতেও যদি এরকম প্রজেক্ট চালু করা যায়, আশা করি শিক্ষাক্ষেত্রে এক বড় ধরনের বিপ্লব ঘটাতে যাচ্ছি আমরা। বিশ্বব্যাংকের এই প্রজেক্ট অনুসরণ করে শ্রীলংকা, মালয়েশিয়ার শিক্ষাব্যবস্থা আজকের এই পর্যায়ে এসেছে। আমরাও নিশ্চয়ই আগামীতে এরকম আন্তর্জাতিক মানের উচ্চাসনে যেতে পারবো।

7
Other than physical facility what else does a human being think about?
The list of thoughts can be classified into two categories:
1.   Feeling in relationship with other human being
2.   Right understanding in the self, or knowledge

Human being think about ensuring these, in addition to physical facility.
If we recognize human being’ aspiration, we find that they want to live in relationship with all and feel happy living in relationship, therefore relationship is necessary for human being.

Examine within yourself if
1.   You want to live in relationship (harmony) with others or
2.   You want to live in opposition with others or
You believe living has to be necessarily in opposition with others, i.e. There is 'struggle for survival',  ‘survival of the fittest’ and  check if you feel happy living this way?
Every night when there is a fight, we want to resolve it. We start the next day with the thought that we don’t want to fight today, but due to lack of right understanding about fulfillment of relationship, a fight takes place by night.
For fulfillment in relationship, it is necessary to have right understanding about relationship. i.e. Right understanding is also necessary for human being.

Right understanding, relationship and physical facility – among three which one has more priority?
Right understanding and relationship make mutual happiness.
Right understanding and physical facility make mutual prosperity. So, right understanding has first priority, relationship has second priority and so on.

If we only looking for physical facility without prioritize the right understanding and relationship, then unhappiness and deprivation will take place.

Therefore we can observe two categories of human being:
1.   Lacking physical facility, unhappy deprived
2.   Having physical facility, unhappy deprived
While we want to be –
3.   Having physical facility, happy prosperous

Check within yourself
   Where are you now – at 1, 2 or 3 and
   Where do you want to be?

If we are living for all three (right understanding, relationship and physical facility) then we are living with human consciousness.
The role of education is to facilitate the development of the competence to live with Definite Human Conduct.
Holistic development is transformation to Human Consciousness.

For this, the education-reformation has to ensure
1.   Right understanding in the self of every child
2.   The capacity to live in relationship with the other human being
3.   The capacity to identify the need of physical facility and the skills & practice for sustainable production of more than what is required leading to the feeling of prosperity

These are the 3 components of human education-reformation, if it has to ensure development of definite human conduct.


courtesy: Dr. Kumar Samvab



8
Whatever is said is a Proposal, Verify it on Your Own Right – on the basis of your Natural Acceptance.

A dialogue between me and you, to start with It soon becomes a dialogue within your own self.

The role of education is to facilitate the development of the competence to live with Definite Human Conduct. Conduct in accordance with one's Natural Acceptance.

Think on it.

Out of the three types of fear, which is predominant for you?
   Fear of Natural Calamities
   Fear of Wild Animals
   Fear of the Inhuman Behaviour of Human Being
Is this on the increase or decrease?

If Literacy is increasing, the fear of the Inhuman Behaviour of Human Being is also increasing…

A news report showed that in India by 2011 literacy is increased by 74%. But values are declined day by day.

The role of education-reformation is to facilitate the development of the competence to live with Definite Human Conduct.

Now the question is that who is responsible to make it available?
Parents, Teachers, Society?

If we want to provide such education-reformation, what would be the basic requirements?

We can examine us,
Is Human Relationship Important?
What do we all want?
Do we want to be happy?
Do we want to be prosperous?
Do we want the continuity of happiness and prosperity?
Are we happy?
Are we prosperous?
Is there continuity of our happiness and prosperity?

Is our effort
–   For continuity of happiness and prosperity?
–   Just for accumulation of physical facility?
Have we assumed that happiness and prosperity will be ensured when we have enough physical facility?
What effort are we making for continuity of happiness and prosperity, other than accumulation of physical facility?

We can think about that

The unhappiness in our family is
   More due to lack of physical facility or
   More due to lack of fulfillment in relationship?
How much time and effort are we investing:
   For physical facility
   For fulfillment in relationship

The answer is that the unhappiness is more due to lack of fulfillment in relationship. Most of the time and effort is spent for physical facility.
For human being physical facility is necessary but relationship is also necessary.
On examining carefully, we find that this is a fundamental difference between animals and human being?
Physical facility is necessary for animals and necessary for human being also. But it is adequate for animal, not for human being.


Courtesy: Prof. Kumar Samvab

9
Telecom Forum / Subcriber Identification Number (SIM, RIM)
« on: February 15, 2016, 05:21:20 PM »
A subscriber identity module (SIM) is a smart card inside of a GSMcellular phone that encrypts voice and data transmissions and stores data about the specific user so that the user can be identifiedand authenticated to the network supplying the phone service. The SIM also stores data such as personal phone settings specific to the user and phone numbers. A SIM can be moved from one phone to another and/or different SIMs can be inserted into any GSM phone. For example, if a user has one phone but uses it for both personal and business calls, he can change the SIM depending on how he will be using the phone (one card contains his personal identity and data and the second card carries his business identity and data).
A SIM also is referred to as a SIM card.

A SIM card and can be switched easily from one phone set to another. The portability of data offers a number of benefits. For example, a user that buys a new phone can install the current SIM card to associate the new phone with the same number and user preferences as the old one. In another common situation, if a phone's battery runs out of power, the user can easily install the card to another subscriber's phone to borrow it without running up that user's minutes. Some vendors offer prepaid SIM cards that can provide travelers with local numbers, as long as their cell phones are not locked to a specific carrier.

Removable User Identity Module (R-UIM) is a card developed for cdmaone/CDMA2000 ("CDMA") handsets that extends the GSM SIM card to CDMA phones and networks. To work in CDMA networks, the R-UIM contains an early version of the CSIM application. The card also contains SIM (GSM) application, so it can work on both networks. It is physically compatible with GSM SIMs and can fit into existing GSM phones as it is an extension of the GSM 11.11 standard
This interface brings one of the main advantages of GSM to CDMA network phones. By having a removable identity card, CDMA users can change phones while keeping their phone numbers by simply swapping the cards. This simplifies many situations such as phone upgrades, phone replacements due to damage, or using the same phone on a different provider's CDMA network.
The R-UIM card has been superseded by CSIM on UICC. This technique allows all three applications (SIM, CSIM, and USIM) to coexist on a single smartcard, allowing the card to be used in virtually any phone worldwide that supports smart cards.
This form of card is widely used in China under the CDMA service of China Telecom (The CDMA service of China Telecom was acquired from China Unicom in 2008). However, it is also used elsewhere such as India, Indonesia, Japan, Taiwan, Thailand, and the US.

ICCID
Each SIM is internationally identified by its integrated circuit card identifier (ICCID). ICCIDs are stored in the SIM cards and are also engraved or printed on the SIM card body during a process called personalisation. The ICCID is defined by the ITU-T recommendation E.118 as the Primary Account Number. Its layout is based on ISO/IEC 7812. According to E.118, the number is up to 22 digits long, including a single check digit calculated using the Luhn algorithm. However, the GSM Phase 1[8] defined the ICCID length as 10 octets (20 digits) with operator-specific structure.
The number is composed of the following subparts:

Issuer identification number (IIN)
Maximum of seven digits:
•   Major industry identifier (MII), 2 fixed digits, 89 for telecommunication purposes.
•   Country code, 1–3 digits, as defined by ITU-T recommendation E.164.
•   Issuer identifier, 1–4 digits.
Individual account identification
•   Individual account identification number. Its length is variable, but every number under one IIN will have the same length.
Check digit
•   Single digit calculated from the other digits using the Luhn algorithm.
With the GSM Phase 1 specification using 10 octets into which ICCID is stored as packed BCD, the data field has room for 20 digits with hexadecimal digit "F" being used as filler when necessary.
In practice, this means that on GSM SIM cards there are 20-digit (19+1) and 19-digit (18+1) ICCIDs in use, depending upon the issuer. However, a single issuer always uses the same size for its ICCIDs.

International mobile subscriber identity (IMSI)
SIM cards are identified on their individual operator networks by a unique International Mobile Subscriber Identity (IMSI). Mobile network operators connect mobile phone calls and communicate with their market SIM cards using their IMSIs. The format is:
•   The first three digits represent the Mobile Country Code (MCC).
•   The next two or three digits represent the Mobile Network Code (MNC). Three-digit MNC codes are allowed by E.212 but are mainly used in the United States and Canada.
•   The next digits represent the Mobile Subscriber Identification Number (MSIN). Normally there will be 10 digits but would be fewer in the case of a 3-digit MNC or if national regulations indicate that the total length of the IMSI should be less than 15 digits.
•   Digits are different from country to country.

Authentication key (Ki)
The Kni is a 128-bit value used in authenticating the SIMs on the mobile network. Each SIM holds a unique Ki assigned to it by the operator during the personalization process. The Ki is also stored in a database (termed authentication center or AuC) on the carrier's network.
The SIM card is designed not to allow the Ki to be obtained using the smart-card interface. Instead, the SIM card provides a function, Run GSM Algorithm, that allows the phone to pass data to the SIM card to be signed with the Ki. This, by design, makes usage of the SIM card mandatory unless the Ki can be extracted from the SIM card, or the carrier is willing to reveal the Ki. In practice, the GSM cryptographic algorithm for computing SRES_2 (see step 4, below) from the Ki has certain vulnerabilities[9] that can allow the extraction of the Ki from a SIM card and the making of a duplicate SIM card.

Authentication process:
1.   When the Mobile Equipment starts up, it obtains the International Mobile Subscriber Identity (IMSI) from the SIM card, and passes this to the mobile operator requesting access and authentication. The Mobile Equipment may have to pass a PIN to the SIM card before the SIM card will reveal this information.
2.   The operator network searches its database for the incoming IMSI and its associated Ki.
3.   The operator network then generates a Random Number (RAND, which is a nonce) and signs it with the Ki associated with the IMSI (and stored on the SIM card), computing another number, that is split into the Signed Response 1 (SRES_1, 32 bits) and the encryption key Kc (64 bits).
4.   The operator network then sends the RAND to the Mobile Equipment, which passes it to the SIM card. The SIM card signs it with its Ki, producing SRES_2 and Kc, which it gives to the Mobile Equipment. The Mobile Equipment passes SRES_2 on to the operator network.
5.   The operator network then compares its computed SRES_1 with the computed SRES_2 that the Mobile Equipment returned. If the two numbers match, the SIM is authenticated and the Mobile Equipment is granted access to the operator's network. Kc is used to encrypt all further communications between the Mobile Equipment and the network.

Location area identity
The SIM stores network state information, which is received from the Location Area Identity (LAI). Operator networks are divided into Location Areas, each having a unique LAI number. When the device changes locations, it stores the new LAI to the SIM and sends it back to the operator network with its new location. If the device is power cycled, it will take data off the SIM, and search for the prior LAI.

10
Telecom Forum / Internet of Things
« on: September 07, 2015, 12:04:36 PM »
The Internet of Things (IoT), also called Internet of Everything or Network of Everything, is the network of physical objects or "things" embedded with electronics, software, sensors, and connectivity to enable objects to exchange data with the production, operator and/or other connected devices based on the infrastructure of International Telecommunication Union's Global Standards Initiative.

The term “Internet of Things” was coined by British entrepreneur Kevin Ashton in 1999. Typically, IoT is expected to offer advanced connectivity of devices, systems, and services that goes beyond machine-to-machine communications (M2M) and covers a variety of protocols, domains, and applications.

Environmental monitoring
Environmental monitoring applications of the IoT typically utilize sensors to assist in environmental protection by monitoring air or water quality, atmospheric or soil conditions, and can even include areas like monitoring the movements of wildlife and their habitats. Development of resource constrained devices connected to the Internet also means that other applications like earthquake or tsunami early-warning systems can also be used by emergency services to provide more effective aid. IoT devices in this application typically span a large geographic area and can also be mobile.

Medical and healthcare systems
IoT devices can be used to enable remote health monitoring and emergency notification systems. These health monitoring devices can range from blood pressure and heart rate monitors to advanced devices capable of monitoring specialized implants, such as pacemakers or advanced hearing aids. Specialized sensors can also be equipped within living spaces to monitor the health and general well-being of senior citizens, while also ensuring that proper treatment is being administered and assisting people regain lost mobility via therapy as well. Other consumer devices to encourage healthy living, such as, connected scales or wearable heart monitors, are also a possibility with the IoT. More and more end-to-end health monitoring IoT platform are coming up for antenatal and chronic patients, helping one manage health vitals and recurring medication requirements. Distinct advantages over similar products from the US and Europe are cost-effectiveness and personalisation for chronic patients. Doctors can monitor the health of their patients on their smartphones after the patient gets discharged from the hospital.


https://en.wikipedia.org/wiki/Internet_of_Things


11
Telecom Forum / Smart Cities: Reviewing what makes a city smart
« on: September 07, 2015, 11:31:10 AM »
Telefónica has a four pillar guideline that serves as a best practices guide of how to turn cities into Smart Cities:

Go hand in hand with citizens
The citizen must perceive Smart City improvements as advances that provide better and more efficient municipal services enhancing life in the city. Smart Cities must inevitably improve pre-existent conditions substantially in order to justify investment and the logical inconveniences during the initial deployment.

Open for business
It is key to adopt an integrating vision when planning Smart Cities. The best option is to opt for open standards with a holistic perspective that easily integrate any potential technological partners in the platform and ensure continuity in time. Smart Cities should always use top down design approaches with the citizen in the center: the final objective is always to offer better services to the citizenship.

Each layer of technology is set to serve the next in a four tier architecture:

Sensors > Connectivity > Management Platform > Analysis and Intelligence

The European Union is so far the part of the world where more efforts have been made to develop smart cities.

The best partnerships provide the best results
Having solid technological partners with proven know-how to efficiently deploy these services and maintain them in good shape is fundamental in order to meet citizen’s expectations

Expect the best from the best. Seeking expertise and market leadership implementing solutions is a sound approach to achieve optimal results. Best in class partners provide their portfolio of top class solutions and the necessary experience to successfully deliver projects within the planned scenario timeframe and budget.

Involving startups and SMEs
It takes more than a group of large corporations to deploy and maintain Smart Cities. Disruptive technology is often introduced by smaller startups with bold and innovative ideas. It would be a mistake to rule small companies out of this transformation process as they have an important role to complement successful Smart City developments.

http://www.telecomstechnews.com/news/2015/aug/17/reviewing-what-makes-a-smart-city-smart/

12
With a view to target applications in machine to machine (M2M) and industrial Internet of Things (IoT), Gemalto has rolled out the new Cinterion ELS31, a novel LTE Category 1 wireless module to enhance 4G LTE connectivity.

Providing power optimisation and single-mode LTE at speeds of up to 10Mbit/s download and 5Mbit/s uplink, the module is well-suited to IoT applications like metering, tracking and tracing, fleet management and mHealth.

The module can function at operating temperatures from -40°C to 85°C and can facilitate migration to LTE from 2G and 3G devices. Available with Full Type Approval and local network operator certifications, the module is the first among the company’s M2M-optimized LTE products.

Josh Builta, associate director of M2M at IHS, said, “Mobile networks worldwide are rapidly evolving to LTE, but the vast majority of industrial M2M and IoT solutions don’t require high-speed 4G bandwidth for optimal performance. LTE Cat 1 modules however provide performance and features that are optimal for most industrial applications, and deliver a cost-effective way to alleviate customers' long-term future proofing concerns.”

http://www.telecomstechnews.com/news/2015/sep/03/gemalto-rolls-out-industry-first-m2m-module-target-industrial-internet-things/

13
good one!

14
Telecom Forum / Class 4 and Class 5 Switch/ Softswitch
« on: August 08, 2015, 12:53:41 PM »
A class-4, or tandem, telephone switch is a central office telephone exchange used to interconnect local exchange carrier offices for long distancecommunications in the public switched telephone network.
A class-4 switch doesn't connect directly to any telephones; instead, it connects to other class-4 switches and to class-5 telephone switches. The telephones of service subscribers are wired to class-5 switches. When a call is placed to a telephone that is not on the same class-5 switch as the subscriber, the call may be routed through one or more class-4 switches to reach its destination.
a class-4 switch that connects class-5 switches to the long-distance network is called an "access tandem." A class-4 switch that connects class-5 switches to each other, but not to the long-distance network, is called a "local tandem."

A class-5 telephone switch is a telephone switch or telephone exchange in the public switched telephone network located at the local telephone company's central office, directly servingsubscribers. Class-5 switch services include basic dial-tone, calling features, and additional digital and data services to subscribers using the local loop. Class-5 switches were slower to convert from circuit switching technologies to time division multiplexing than the other switch classes.
The fundamental difference between a class-5 and the other classes of exchange is that a class-5 switch provides telephone service to customers, and as such is concerned with "subscriber type" activities: generation of dial-tone and other "comfort noises"; handling of network services such as advice of duration and charge etc. Specifically, a class-5 switch provides dial tone, local switching and access to the rest of the network. class-4 switches do not provide dial tone – they simply route calls between other switches, so they are more concerned with efficient switching and signalling.
Typically a class-5 switch covers an area of a city, an individual town, or several villages and could serve from several hundred to 100,000 subscribers.
In the British telephone network, a class-5 switch is known as digital local exchange (DLE).

Softswitches are also subdivided into two classes. Class 4 softswitches and Class 5 softswitches.
Softswitches used for transit VoIP traffic between carriers are usually called class 4 softswitches. Analogous with other Class 4 telephone switches, the main function of the class 4 softswitch is the routing of large volumes of long distance VoIP calls. The most important characteristics of class 4 softswitch are protocol support and conversion, transcoding, calls per second rate, average time of one call routing, number of concurrent calls.
Class 5 softswitches are intended for work with end-users. These softswitches are both for local and long distance telephony services. Class 5 softswitches are characterized by additional services for end-users and corporate clients such as IP PBX features, call center services, calling card platform, types of authorization,QoS,Business Groups and other features similar to other Class 5 telephone switches.

15
Telecom Forum / মোবাইল ফোনের ইতিহাস
« on: August 08, 2015, 12:12:42 PM »
মোবাইল ফোন, সেলফোন, মুঠোফোন বা সেলুলার ফোন যা-ই বলেননা কেন, এটা যে আমাদের জীবনের কতটা যায়গা দখল করে নিয়েছে সেটা বুঝতে পারবেন যদি একটা মাত্র দিন জিনিসটাকে হাত থেকে দূরে রাখেন। অথচ আমরা অনেকেই এর ইতিহাস সমন্ধে যথেষ্ট জানিনা। আবিস্কারকের নাম বলতে পারেন এমন লোকের সংখ্যাও দেখেছি অনেক কম। আসুন জেনে নিই মোবাইল ফোন আবিস্কার সম্পর্কিত কিছু তথ্য।

Cave Radio ধারণার উদ্ভব হয় সেই ১৯০৮ সালে, যেটাকে সেলুলার ফোনের জন্মসূত্র ধরা হয়। যদিও বাস্তবের মোবাইল ফোন এসেছে অনেক দেরিতে। দুই বছর পর ১৯১০ সালে Lars Magnus Ericsson তার গাড়িতে টেলিফোন লাগিয় ফেলেন, ভ্রাম্যমান ফোন হিসেবে এটার নামই প্রথম আসে। যদিও Ericsson-এর ফোনটা ঠিক Radio Phone ছিলোনা। ভদ্রলোক তাঁর গাড়ি নিয়ে দেশময় ঘুরে বেড়াতেন এবং প্রয়োজন হলেই গাড়ি থামিয়ে ফোনের সাথে লম্বা দুইটা তার লাগিয়ে নিতেন, তারপর National Phone Network ব্যবহার করে ফোন করার কাজ সারতেন !!
সমসাময়িক ইউরোপের ট্রেনগুলোতে প্রথম শ্রেনীর যাত্রীরা Radio Telephone ব্যবহারের সুযোগ পেতেন। এই সুবিধা ছিলো বার্লিন থেকে হামবুর্গ পর্যন্ত সীমাবদ্ধ। একই সময় বিমানের যাত্রীরা নিরাপত্তার খাতিরে রেডিও টেলিফোন সুবিধা পেতেন। এ জাতীয় ফোনের ব্যাপক ব্যবহার হয় দ্বিতীয় বিশ্বযুদ্ধের সময়। জার্মানী মূলত ব্যাপক প্রচলন ঘটায় । সৈন্যরা যোগাযোগের জন্যে এটাকে ব্যবহার করত।
আমরা যে মোবাইল ফোন কে চিনি তার জন্ম ১৯৭৩ সালে। আজকের বিখ্যাত মোবাইল ফোন নির্মাতা কোম্পানী মটরোলার হাত ধরে যাত্রা শুরু করে সেলুলার ফোন। নাম দেওয়া হয় DynaTAC 8000X। কিন্তু এই ফোনটাতে কোনো ডিসপ্লে ছিলোনা।
১৯৭৩ সালের ৩ এপ্রিল মটরোলার কর্মকর্তা Dr. Martin Cooper বেল ল্যাবস-এর কর্মকর্তা Dr. Joels Engel-এর সাথে বিশ্বের ইতিহাসে প্রথমবারের মত মোবাইল ফোনে কথা বলেন। আর মোবাইল ফোনের ইতিহাসের সাথে জড়িয়ে যায় এই দুই বিজ্ঞানী, মটরোলা আর বেল ল্যাবস-এর নাম। অবশ্য Radio Telephone System-এর আবিস্কারক হিসেবে মার্টিন কুপার আর তাঁর গুরু Motorola Portable Communication Products-এর চীফ John F. Michel নাম US Patent-এ (Patent no. 3,906,166) লিপিবদ্ধ হয় ১৭ অক্টোবর ১৯৭৩ সালে।
জেনারেশন ভিত্তিক মোবাইল ফোনের ইতিহাস বেশ কয়েকটা অংশে বিভক্ত (যেমনঃ 1G, 2G, 2.5G, 2.75G, 3G, 4G ), এইগুলো নিয়ে পরে আলোচনা করবো।
ছবিতে (প্রথম সেলুলার ফোন হাতে মার্টিন কুপার)

(সংগৃহীত)

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