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Guide to Mobile Services And Standards

Mobile Generation:-
This is the first-generation telecommunication standard for mobile phones. It was prevalent in the 1980s and early 1990s and used analogue radio signals. It has been almost phased out.

Successor to 1G, the second-generation standards used digital radio signals. This meant that voice signals could be encoded and multiplexed,resulting in more data being squeezed over the airwaves.The voice quality improved considerably, and the kind of static heard on 1G networks is absent. The digital systems also emit lower
power. Lower power means that the devices can be smaller, and that the towers become more inexpensive to set up and maintain.2G networks comprise mainly TDMA and CDMA networks,depending on the type of multiplexing i.e. the way in which the multiple radio waves are combined into a single stream. TDMA standards can be further divided into GSM.
Third-generation networks deliver faster data speeds over existing 2G networks and also more types of services like broadband access and video telephony. The typical data transfer rates over 3G networks are in the region of 5-10 Megabits per second. Depending on location, 3G networks use either the same spectrum as 2G (in the US) or a different spectrum (in Asia and Europe). 3G-enabled phones are prevalent mostly in Europe and parts of Asia like South Korea and Japan. 3G-derived technologies include HSPA (High Speed Packet Access), WCDMA (Wideband Code Division Multiple Access), and UMTS (Universal Mobile Telecommunication System).
Fourth-generation wireless networks are intended to provide a solution where voice, data, and video can be accessed seamlessly without any bottlenecks. To be implemented using the IP protocol stack, 4G networks will provide connection speeds ranging from 100 Mbps to 1 Gbps, with assured security, high quality, and low cost. These networks will interoperate with existing networks and deliver applications like real-time streaming video, HDTV, and high-volume data.
Mobile Network:-
Code Division Multiple Access is an alternative technology to GSM for 2G and 3G networks. In CDMA, voice signals are digitised, and the frequency of the transmitted signal is varied according to a predefined code. This signal can only be intercepted by a receiver whose frequency response is programmed to vary with the same code. Since there are trillions of frequency-shifting sequences, CDMA signals offer considerable privacy. These signals use the 800 MHz and 1.9 GHz bands. CDMA signals utilise more bandwidth compared to GSM signals because of the variations in frequency. CDMA handsets are typically locked by carriers, which means you cannot switch your carrier without changing your
Circuit Switched Data is a form of data transmission developed for TDMA networks like GSM. In this system, time slots are used to deliver data at the rate of 9.6 Kilobits per second. A newer variant is High Speed CSD (HSCSD) which employs more time slots and efficient coding methods to deliver data at enhanced rates.
Evolution-Data Optimised is a 3G protocol for wireless data transmission used mostly for broadband Internet access. EV-DO uses CDMA to transmit data at speeds of 500 to 1000 Kilobits per second, and is not compatible with GSM networks. Where signal  strength is strong, EVDO enables a zone of pervasive computing where multiple devices can seamlessly use high-speed Internet access. Its primary competitor is HSDPA, which allows simultaneous voice and data transmission.

General Packet Radio Service is a data transfer method used with GSM networks. In this method, data is transferred in packets using the Internet Protocol (IP), rather than in streams. Data transfer rates for GPRS vary from 56 to 114 Kilobits per second. It is a step slower than the EDGE (Enhanced Data GSM Environment) protocol, which delivers data at maximum rates of 384 Kilobits per second. Apple’s iPhone is a GPRS / EDGE enabled device.
Global System for Mobile communications is a 2G mobile network technology and currently the most popular globally, with a market share of more than 80 per cent. It is used by about 700 operators in 214 countries, covering 29 per cent of the global population. In GSM, voice signals are digitised, then compressed, and sent along with two similar data streams in different time slots but the same frequency spectrum (900 MHz or 1800 MHz). This indicates that it uses TDMA (Time Division Multiple Access) to send data. GSM networks also offer a degree of data encryption.
High Speed Packet Access is based on the UMTS protocol. It is divided into two standards: HSDPA (HS Downlink PA) and HSUPA (HS Uplink PA). HSDPA is also known as “3.5G” and has theoretical data transfer rates of 8 ~ 10 Megabits per second. Multimedia and streaming video is the primary focus of HSDPA networks. Most new high-end phones come with HSDPA services enabled, though very few carriers support these high speeds.
Universal Mobile Telecommunication System is a 3G-based wireless communication technology for cell phones using WCDMA as the air interface. UMTS is also called 3GSM because the protocol was intended to succeed GSM networks, and also used the GSM infrastructure to connect.
Wireless Access Protocol is designed to enable Internet access from mobile phones. This is done by using a special browser called a WAP browser (Opera Mini, for example), a simplified form of the Desktop browser, and accessing Web sites written in WML (Wireless Markup Language). Though WAP was projected to provide full functionality for Web browsing in phones, the attempt has not been successful because of technical and design issues.

Wideband CDMA is a 3G standard for wireless data access and is designed to provide higher access speeds than the 2G GSM networks. WCDMA is used mostly in Europe and Asia (particularly Japan). It is called wideband because while CDMA transmits on one or more pairs of 1.25 MHz channels, WCDMA transmits data on a pair of 5 MHz channels.

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