What Is Mobile?
" Mobile means mobility or which lets you move. "
The term " Mobile " implies portability; so, a mobile device, such as a Palm Pilot, is one that easily travels with you. The term also commonly implies that the device has an " always on " connection to the internet. So we see that the adjective mobile denotes two different scenarios: offline and online. Mobile offline means that you can use the device to run self-contained programs without a live Internet connection.
You can " sync " with a PC to download software, e-mail messages, and other content onto your PDA for portable reading or offline reference. Data collected on the road can be synchronized with a PC once you get back to the office or the office or upload whenever an Internet connection is established. The handheld scanners that FedEx drivers use to capture delivery information, such as signature, are a good example of a mobile but offline device.
When the driver returns to the delivery van, he can sync the handheld scanner with an onboard computer, and the information is upload into the FedEx network. In the figure given below, you can see online offline mobile scenarios. Mobile online is commonly called wireless. This means that users are connected to the Internet via satellite, cellular, or radio transmitters.
An online device will be " always on " in the presence of any wireless data network - seamlessly connecting to the Internet so it can exchange e-mail and instant message and retrieve web content. The extremely popular BlackBerry RIM handhelds are capable of all these activities and, notably, allow users to securely access corporate e-mail accounts.
Architecture Of Mobile Communication: Each mobile uses a separate, temporary radio channel to talk to the cell site base station mobile. Channels use a pair of communication one frequency, the forward link, for transmitting from the cell site and one frequency, the reverse link, for the call site to receive calls from the users.
Radio energy dissipates over distance, so mobiles must stay near the base station to maintain communication. Code 's convert an analog speech signal to its digital representation by sampling the analog signal at regular time intervals called pulse code modulation. For analog data to be transmitted analog modulation techniques like amplitude modulation and frequency modulation are used. The modulation techniques used for digital signal transmission are amplitude shift keying, frequency shift keying, phase shift keying.
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| What Is Mobile? |
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