Comparison table[edit]

Feature	NMT	GSM	UMTS (3GSM)	IS-95 (CDMA one)	IS-2000 (CDMA 2000)	LTE
Technology	FDMA	TDMA and FDMA	W-CDMA	CDMA	CDMA	OFDMA
Generation	1G	2G	3G	2G	3G	4G
Encoding	Analog	Digital	Digital	Digital	Digital	Digital
Year of First Use	1981	1991	2001	1995	2000 / 2002	2009
Roaming	Nordics and several other European countries	Worldwide, all countries except Japan and South Korea	Worldwide	Limited	Limited	Limited
Handset interoperability	None	SIM card	SIM card	None	RUIM (rarely used)	SIM card
Common Interference	None	Some electronics, e.g. amplifiers	None	None	None	None
Signal quality/coverage area	Good coverage due to low frequencies	Good coverage indoors on 850/900 MHz. Repeaters possible. 35 km hard limit.	Smaller cells and lower indoors coverage on 2100 MHz; equivalent coverage indoors and superior range to GSM on 850/900 MHz.	Unlimited cell size, low transmitter power permits large cells	Unlimited cell size, low transmitter power permits large cells
Frequency utilization/Call density	Very low density	0.2 MHz = 8 timeslots. Each timeslot can hold up to 2 calls (4 calls with VAMOS) through interleaving.	5 MHz = 2 Mbit/s. 42Mbit/s for HSPA+. Each call uses 1.8-12 kbit/s depending on chosen quality and audio complexity.	Lower than CDMA-2000?	1.228  MHz = 3Mbit/s
Handoff	Hard	Hard	Soft	Soft	Soft	Hard
Voice and Data at the same time	No	Yes GPRS Class A	Yes[2]	No	No EVDO / Yes SVDO[3]	No (data only) Voice possible through VoLTE or fallback to 2G/3G

Revision and network compatibility
Standard or Revision	Network Compatibility
GSM (1991), GPRS (2000), EDGE (2003)	GSM (2G, TDMA)
cdmaOne (1995)	cdmaOne (2G, CDMA)
EV-DO (1999), Rev. A (2006), Rev. B (2006), SVDO (2011)	CDMA2000 (3G, CDMA/TDMA)
UMTS (1999), HSDPA (2005), HSUPA (2007), HSPA+ (2009)	UMTS (3G, CDMA)
LTE (2009, 3G), LTE Advanced (2011, 4G)	4g on

What is a web app?

Previously, we talked about how desktop applications allow you to perform tasks on your computer. But there are also web applications—or web apps—that run in the cloud and do not need to be installed on your computer. Many of the most popular sites on the Internet are actually web apps. You may have even used a web app without realizing it! Let's take a look at some popular web apps.

• Facebook: Facebook lets you create an online profile and interact with yourfriends. Profiles and conversations can be updated at any time, so Facebook uses web app technologies to keep the information up to date.

• Pixlr: Pixlr is an image editing application that runs in your web browser. Much like Adobe Photoshop, it includes many advanced features, like color correction and sharpening tools.

• Google Docs: Google Docs is an office suite that runs in your browser. Much like Microsoft Office, you can use it to create documents, spreadsheets, presentations, and more. And because the files are stored in the cloud, it's easy to share them with others.

What is a mobile device?

A mobile device is a general term for any type of handheld computer. These devices are designed to be extremely portable, and they can often fit in your hand. Some mobile devices—like tablets, e-readers, and smartphones—are powerful enough to do many of the same things you can do with a desktop or laptop computer.

Tablet computers

Like laptops, tablet computers are designed to be portable. However, they provide a different computing experience. The most obvious difference is that tablet computers don't have keyboards or touchpads. Instead, the entire screen is touch-sensitive, allowing you to type on a virtual keyboard and use your finger as a mouse pointer.

Tablet computers can't necessarily do everything traditional computers can do. For many people, a traditional computer like a desktop or laptop is still needed in order to use some programs. However, the convenience of a tablet computer means it may be ideal as a second computer.

E-readers

E-book readers—also called e-readers—are similar to tablet computers, except they are mainly designed for reading e-books (digital, downloadable books). Notable examples include the Amazon Kindle, Barnes & Noble Nook, and Kobo. Most e-readers use an e-ink display, which is easier to read than a traditional computer display. You can even read in bright sunlight, just like if you were reading a regular book.

You don't need an e-reader to read e-books. They can also be read on tablets, smartphones, laptops, and desktops.

№12 LECTURE