WAP SERVICES
The growth of the Internet, Internet-based application and mobile application led to the availability of several early proprietary solutions providing Internet Services for mobile and wireless divices. In June 1997, the Wireless Application Protocol (WAP) forum was founded with a basic objective to make available dynamic Internet content (e.g. web pages, Push Services) and other data services (e.g. stock Quotes Mobile Commerce etc.) to digital cellular phones and other wireless devices. WAP brings the computing power to a wireless handset, thereby opening an extensive new market for information access. 'Moreover, WAP protocol suite is meant to enable global wireless communication across different wireless technologies e.g. GSM, GRPS, UMTS and 3G. Each of them can be briefly described as follows:
Global System for Mobile Communications (GSM): During the early 1980, Europe had more than a handful of different, completely incompatible anolog mobile phone standards, and manufacturers and implementers were left confused with what ;;tandards to follow. In 1982 the conference of European Posts and Telegraphs (CEPT) formed a study group called the Group Special Mobile (GSM) to study and develop a Pan-European public land mobile system. The proposed system had to meet certain criteria:

In 1989, GSM responsibility was transfered to the European Telecommunication Standard Institute (ETSI) and phase I of the GSM specifications was published in 1990. Commercial service was started in mid-1991, and by 1993 there were 36 GSM networks in 22 countries. GSM systems exist on every continent, and the acronym GSM now aptly stands for Global System for Mobile Communications.
Global Systems for Mobile Communication (GSM) was started, functioning at 900 MHz and supports 124 full-duplix channels. The GSM offers full international roaming, automatic location services, authentication and encryption on the wireless links, efficient interoperation with ISDN Systems and relatively high audio quality.
General packet radio services: General packet radio services (GPRS) is a more flexible service providing powerful data transmission and is devoid of certain defects faced in the previous bearer services. It is fully packet oriented, and provides packet mode transfer for applications that exhibit traffic patterns such as frequent transmission of small volumes (e.g. typical web requets) or infrequent transmissions of small to medium volumes (e.g. typical web responses).
Universal mobile telecommunications systems: Universal mobile tele­communications systems (UMTS) uses enhanced modulation scheme and other techniques. It can support a data rate of 384 Kbps using 200 kHz wide carriers. UMTS should provide the bearer, real time and non-real time services, as well as circuit and packet switched transmission.
Third generation technology:     The third generation technology (3G) supports high end transmission of data and voice signals providing a highly flexible environment for WAP services. Using 3G technologies, mobile devices enable visual display of 256 colours and animated images.
Frequency division multiple access:      Frequency division multiple access (FDMA) is a multiplexing (transmission data to multiple receivers simultaneously) techniques, separating users in the domain of frequency, i.e. the available bandwidth is divided into smaller frequencies and each such frequency band could be allocated to different users. Frequency allocation could be either fixed or dynamic. With fixed allocation, frequencies of different channels remain the same at all times, which in turn is termed as pure FDMA. On the other hand, dynamic allocation is demand-driven, and changes frequencies according to requirement.
Analog mobile phone service: Analog mobile phone service (AMPS) uses FDMA, assigns 850 MHz frequency spectrum to cellular operators, and subdivides the spectrum into 25 kHz channels. Though fully digital systems are available, AMPS still exists today mainly due to its coverage of almost 100 per cent of services.

Time division multiple access:    Time division multiple access (TDMA) divides radio channels into time slots, each slot being a small fraction of a second. The available bandwidth is entirely used by one user for the duration of a slot and in the next slot another user uses the entire bandwidth, and so on. These slots are assigned among eight subscribers, which simultaneously increase the capacity of a cell. TDMA-based cellular systems operate at 800 MHz or 1900 MHz in North America and are referred to as Digital Cellular or Personal Communications Services (PCS).
Code division multiple access: Code division multiple access (CDMA) is another multiple access technique employed by cellular operators. This was developed by Qualcomm Corporation. Instead of creating time slots or dividing the radio frequency spectrum into separate channels by frequency, CDMA uses spread spectrum transmission to obtain radio channels much wider than in TDMA and AMPS systems.
CDMA system assigns pseudo random digital codes to each active subscriber. The advantage of CDMA is its ability to extend system capacity. Also, it can provide approximately 10 to 20 times the capacity of analog AMPS and four to six times the
capacity of TDMA. Unlike analog and digital systems, a CDMA system permits a soft hand-of, as it enables a subscriber to monitor and communicate with multiple cells. CDMA also supports the power control with which a CDMA handset can gain the battery life about three times the normal GSM handset.
Cellular digital packet data: Cellular digital packet data (CDPD), commonly referred to as wireless IP, is implemented as an overlay to a communication carrier's existing digital cellular network. Based on TCP/IP, CDPD provides Internet access to mobile users at a transmission rate of 19.2 Kbps.
Wideband CDMA: Wideband CDMA is a direct sequence spreading method with different uplink and downlink frequencies. A mobile station sends the uplink using a carrier between 1920 and 1980 MHz, the base station uses 2100 or 2170 MHz for the downlink. The method roughly provides about 250 channels for user traffic. Each physical channel corresponds to carrier frequency, certain spreading code and a relative phase (for uplink only), and carries a maximum of 2 Mbps data.
Bluetooth: Bluetooth is the name given to a new technology that uses short-range radio links to replace cable(s) connecting portable and/or fixed electronic devices. Though basically a cable replacement technology, its applicable areas are tremendous and are all set to make a major impact on the connectivity market, which the world will witness in the near future. The first Bluetooth consortium was formed in 1998 by Ericsson, INTEL, IBM, NOKIA and TOSHIBA.
It has been designed to function effectively even in noisy environments, and is envisaged that it will bring about the replacement of proprietary cables connecting various peripherals, with a single universal radio link. Its key features are robustness, low complexity, low power and low cost. Bluetooth radio uses a fast acknowledgement and frequency-hopping scheme to make the link robust and secure. Bleutooth radio modules operate in the unlicenced ISM band at 2.4 GHz and avoid interference from other signals by hopping to a new frequency after transmission or reception of a packet. Today, Bluetooth technology is the implementation of a protocol defined by the IEEE 802.15 standards. The standard defines a wireless personal-area network (PAN)Time division multiple access:      Time division multiple access (TDMA) divides radio channels into time slots, each slot being a small fraction of a second. The available bandwidth is entirely used by one user for the duration of a slot and in the next slot another user uses the entire bandwidth, and so on. These slots are assigned among eight subscribers, which simultaneously increase the capacity of a cell. TDMA-based cellular systems operate at 800 MHz or 1900 MHz in North America and are referred to as Digital Cellular or Personal Communications Services (PCS).
Code division multiple access: Code division multiple access (CDMA) is another multiple access technique employed by cellular operators. This was developed by Qualcomm Corporation. Instead of creating time slots or dividing the radio frequency spectrum into separate channels by frequency, CDMA uses spread spectrum transmission to obtain radio channels much wider than in TDMA and AMPS systems.
CDMA system assigns pseudo random digital codes to each active subscriber. The advantage of CDMA is its ability to extend system capacity. Also, it can provide approximately 10 to 20 times the capacity of analog AMPS and four to six times the
capacity of TDMA. Unlike analog and digital systems, a CDMA system permits a soft hand-of, as it enables a subscriber to monitor and communicate with multiple cells. CDMA also supports the power control with which a CDMA handset can gain the battery life about three times the normal GSM handset.
Cellular digital packet data: Cellular digital packet data (CDPD), commonly referred to as wireless IP, is implemented as an overlay to a communication carrier's existing digital cellular network. Based on TCP/IP, CDPD provides Internet access to mobile users at a transmission rate of 19.2 Kbps.
Wideband CDMA: Wideband CDMA is a direct sequence spreading method with different uplink and downlink frequencies. A mobile station sends the uplink using a carrier between 1920 and 1980 MHz, the base station uses 2100 or 2170 MHz for the downlink. The method roughly provides about 250 channels for user traffic. Each physical channel corresponds to carrier frequency, certain spreading code and a relative phase (for uplink only), and carries a maximum of 2 Mbps data.
Bluetooth: Bluetooth is the name given to a new technology that uses short-range radio links to replace cable(s) connecting portable and/or fixed electronic devices. Though basically a cable replacement technology, its applicable areas are tremendous and are all set to make a major impact on the connectivity market, which the world n-ill witness in the near future. The first Bluetooth consortium was formed in 1998 by Ericsson, INTEL, IBM, NOKIA and TOSHIBA.
It has been designed to function effectively even in noisy environments, and is envisaged that it will bring about the replacement of proprietary cables connecting various peripherals, with a single universal radio link. Its key features are robustness,
low complexity, low power and low cost. Bluetooth radio uses a fast acknowledgement and frequency-hopping scheme to make the link robust and secure. Bluetooth radio modules operate in the unlicensed ISM band at 2.4 GHz and avoid interference from other signals by hopping to a new frequency after transmission or reception of a packet.
Today, Bluetooth technology is the implementation of a protocol defined by the IEEE 802.15 standards. The standard defines a wireless personal-area network (PAN)operable in the area of size of a room or a hall. Bluetooth defines two ti networks: piconets and scatternet.
A Bluetooth network is called a piconet or a small net. A piconet can have eight stations, one of which is called the master; the rest are called slave communication between the master and the slaves can be one-to-one or one to Piconet can be combined to form, which is called scatternet.

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