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Mobile Phone

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What is Mobile phone?

A mobile phone (also known as a wireless phone, cell phone, or cellular telephone) is a small portable radio telephone.

The mobile phone can be used to communicate over long distances without wires. It works by communicating with a nearby base station which connects it to the main phone network. When moving, if the mobile phone gets too far away from the cell it is connected to, that cell sends a message to another cell to tell the new cell to take over the call. This is called a "hand off," and the call continues with the new cell the phone is connected to. The hand-off is done so well and carefully that the user will usually never even know that the call was transferred to another cell.

The modern form of mobile phone is called "Smart Phone". It has become very popular. The majority of mobile phones made after 2010 are "smartphones". They can be used as computers as well as making voice calls.

 

History of Mobile phone:-

In 1917, Finnish inventor Eric Tigerstedt filed a patent for a "pocket-size folding telephone with a very thin carbon microphone". Early predecessors of cellular phones included analog radio communications from ships and trains. The race to create truly portable telephone devices began after World War II, with developments taking place in many countries. The advances in mobile telephony have been traced in successive "generations", starting with the early zeroth-generation (0G) services, such as Bell System's Mobile Telephone Service and its successor, the Improved Mobile Telephone Service. These 0G systems were not cellular, supported few simultaneous calls, and were very expensive.

The first handheld mobile phone was demonstrated by John F. Mitchell and Martin Cooper of Motorola in 1973, using a handset weighing c. 4.4 lbs (2 kg). The first commercial automated cellular network was launched in Japan by Nippon Telegraph and Telephone in 1979. This was followed in 1981 by the simultaneous launch of the Nordic Mobile Telephone system in Denmark, Finland, Norway, and Sweden. Several other countries then followed in the early to mid-1980s. These first-generation (1G) systems could support far more simultaneous calls but still used analog cellular technology. In 1983, the DynaTAC 8000x was the first commercially available handheld mobile phone.

In 1991, the second-generation (2G) digital cellular technology was launched in Finland by Radiolinja on the GSM standard. This sparked competition in the sector as the new operators challenged the incumbent 1G network operators.

Ten years later, in 2001, the third generation (3G) was launched in Japan by NTT DoCoMo on the WCDMA standard. This was followed by 3.5G, 3G+ or turbo 3G enhancements based on the high-speed packet access (HSPA) family, allowing UMTS networks to have higher data transfer speeds and capacity.

By 2009, it had become clear that, at some point, 3G networks would be overwhelmed by the growth of bandwidth-intensive applications, such as streaming media. Consequently, the industry began looking to data-optimized fourth-generation technologies, with the promise of speed improvements up to ten-fold over existing 3G technologies. The first two commercially available technologies billed as 4G were the WiMAX standard, offered in North America by Sprint, and the LTE standard, first offered in Scandinavia by TeliaSonera.

 

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How Mobile phones cells handle calls work?

Simple call

If a phone in cell  calls a phone in cell , the call doesn't pass directly between the phones, but from the first phone to mast and its base station, then to mast and its base station, and then to the second phone.

Roaming call

Cell phones that are moving between cells (when people are walking along or driving) are regularly sending signals to and from nearby masts so that, at any given time, the cell phone network always knows which mast is closest to which phone.

If a car passenger is making a call and the car drives between cells, the phone call is automatically "handed off" (passed from cell to cell) so the call is not interrupted.

The key to understanding cells is to realize that cell phones and the masts they communicate with are designed to send radio waves only over a limited range; that effectively defines the size of the cells. It's also worth pointing out that this picture is a simplification; it's more accurate to say that the masts sit at the intersections of the cells, but it's a little easier to understand things as I've shown them.

 

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Effects of Mobile phone on human health:-

1. A new study from Sweden suggests decades of cell phone use can triple your chances for brain cancer.

2. A recent study noted cell phones could be as dirty as public toilet seats, and that the heat phones generate makes a perfect breeding ground for bacteria.

3. Evidence does not support the hypothesis that mobile phone radiation has an effect on the permeability of the blood-brain barrier.

4. Researchers are investigating whether or not blue light could lead to cataracts.

5. A poor night's sleep caused by smartphone light can make it harder to learn.

6. Effects on heart and brain.

 

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Effects of Mobile phone on environment:-

1. Mobile phones use has dangerous effects on our environment including birds, mammals and pet animals.

2. Studies have shown that around 40-50% of the environmental impact of mobile phones occurs during the manufacture of their printed wiring boards and integrated circuits.

3. The average user replaced their mobile phone every 11 to 18 months, and the discarded phones then contribute to electronic waste.

 

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