Mobile Computing

Mobile Technology

         Mobile computing can be defined as a computing environment over physical mobility. This technology enables peoples to access network service at any place, anytime, and anywhere. The user of mobile computing environment will be able to access data, information or other logical objects from any device in any network while on the move. Mobile computing s used in different contexts with different names such as Mobile Computing, Anywhere, Anytime Information, Virtual Home Environment, Nomadic Computing, Ubiquitous Computing, and many others. Computing environment can be defined as mobile if it supports one or more of the characteristics such as User Mobility, Network Mobility, Bearer Mobility, device mobility, session mobility, service mobility, and host mobility.  Mobile computing system allows a user to perform a task from anywhere using a computing device in the public, corporate, and personal information spaces.

            The evolution of mobile computing can be seen through the evolution of wireless data. The evolution of wireless technology has been defined in generations which is the first generation is well known as 1G technology, followed by 2G technology, 3G technology with 2.5G technology followed by 2.75G technology as an intermediate between 2G and 3G technology, and the latest technology is 4G technology.

            1G (or 1-G) refers to the first-generation of wireless telephone technology, mobile communications. 1G technology were introduced at 1980s and an analog telecommunications standards. 1G technology uses FDMA (Frequency Division Multiple Access) technology for modulation. The first 1G network launched was the Nippon Telegraph and Telephone Corporation (NTT) in Japan in 1979. The next 1G network technology is Nordic Mobile Telephone (NMT). NMT is the first fully automatic cellular phone system that introduced. There are two variants of NMT which is NMT-450 and NMT-900 which the numbers indicate the frequency band that uses with NMT-900 carries more channels than NMT-450 network. In 1982, Advance Mobile Phone Technology (AMPS) was introduced by AT&T. Analog AMPS was then superseded by Digital AMPS in 1990.

            In 2G technology, voice is digitized over a circuit. Using modems, a data connection is established between device and the network. This technique is similar to what happen in a dial-up network over analog telephone at home. One of the network technologies in 2G is GSM (global System for Mobile Communications). GSM uses a combination of FDMA (Frequency Division Multiple Access) and TDMA (Time Division Multiple Access). In this 2G network technology, SMS (Short Message Service) was introduced which enable sending and receiving text message to, and from. GSM supports data access over CSD (Circuit Switched Data). GPRS (General Packet Radio Service) is a technology that introduced letter and well known as 2.5G technology. GPRS is the next phase within the evolution of GSM, support data over packets. WAP is a data service supported by GPRS and GSM to access internet and remote data services. Technology 2.7G network introduced a service called EDGE (Enhanced Data rate for GSM Evolution). This technology allows improved data transmission rates, as an extension on top of standard GSM technology. EDGE is considered as pre-3G technology and standardized by 3GPP as part of the GSM family.

            Third Generation or 3G wireless technology uses Spread Spectrum techniques for media access and encoding. In 3G, both data and voice use packets. The 3G evolution allowed mobile telephone users to user audio, video applications and also a graphics using their phone. 3G technologies also offer user to watch streaming video through mobile telephone. 3G is known as high speed IP data networks and mobile broadband. 3G technology uses packet switching rather than circuit switching for data transmission and makes the internet surfing faster and more convenient. UMTS and CDMA2000 are example of 3G networks.

            The latest technology is Fourth Generation or 4G network. 4G technology is design to deliver fast wireless broadband services to mobile devices. 4G network use an encoding method OFDM (Orthogonal Frequency Division Multiplexing). The 4g technology enable more simultaneous user per call which is offer higher reliability and less dropped calls. Example of services in 4G technology network is WiMAX (Worldwide Interoperability for Microwave Access), LTE (Long Term Evolution), and HC-SDMA.