Wireless and Mobile Communication

Transcription

1 Wireless and Mobile Communication Prof. RambabuMakkena,Prof. Sudhir P. Sitanagre Asm`s IBMR Chinchwad, Pune-19, India ABSTRACT The success of mobile communications lies in the ability to provide instant connectivity anytime and anywhere and the ability to provide high-speed data services to the mobile user. The quality and speeds available in the mobile environment must match the fixed networks if the convergence of the mobile wireless and fixed communication networks is to happen in the real sense. So, the challenges for the mobile networks lie in providing a very large footprint of mobile services (to make the movement from one network to another as transparent to the user as possible) and the availability of high speed reliable data services along with high quality voice. Mobile technologies exist today each having influence in specific parts of the world. GSM, TDMA (IS 136), and CDMA (IS 95) are the main technologies in the mobile market. All these systems have different features and capabilities. Although both GSM and TDMA based networks use time division multiplexing on the air interfaces, their channel sizes, structures and core networks are different. The term is often shortened to "wireless". It encompasses various types of fixed, mobile, and portable two-way radios, cellular telephones, personal digital assistants and wireless networking. Wireless operations permits services, such as long range communications, that are impossible or impractical to implement with the use of wireless. The term is commonly used in the telecommunications industry to refer to telecommunications systems. Introduction There are point-to-point wireless bridges, wireless local area networks, multidirectional wireless cellular systems, and satellite communication systems. Cellular Systems and Topology A cell in a cellular system is a roughly circular area with a central transmitter/receiver base stationcells are usually pictured as hexagonal in shape and arranged in a honeycomb pattern. Cell size varies depending on the area. In a city, there are many small cells, Cellular systems are described in multiple generations, with third- and fourth-generation (3G and 4G) 1G systems These are the analog systems such as AMPS that grew rapidly in the 1980s and are still available today 2G systems These second-generation systems are digital, and use either TDMA (Time Division Multiple Access) or CDMA (Code Division Multiple Access) access methods. The European INCON X

2 GSM (Global System for Mobile communications) is a 2G digital system with its own TDMA access methods. The 2G digital services began appearing in the late 1980s, 3G systems 3G has become an umbrella term to describe cellular data communications with a target data rate of 2 Mbits/sec. 4G Systems On the horizon are 4G systems that may become available even before 3G matures (3G is a confusing mix of standards). While 3G is important in boosting the number of wireless calls, 4G will offer true high-speed data services. 4G data rates will be in the 2-Mbit/sec to 156-Mbit/sec GSM (Global System for Mobile Communications) This is a second-generation mobile system designed from the ground up without trying to be backward compatible with older analog systems. GSM is popular in Europe and Asia, where it provides superior roaming ability among countries. It uses TDMA, but Europe is moving from this system into 3G systems based on a wideband form of CDMA. It encompasses various types of fixed, mobile, and portable two-way radios, cellular telephones. Wireless operations permits services, such as long range communications, that are impossible or impractical to implement with the use of wires. The term is commonly used in the telecommunications industry to refer to telecommunications systems (e.g. radio transmitters and receivers, remote controls, computer networks, network terminals, etc.) which use some form of energy (e.g. radio frequency (RF)). MethodologyWireless services The term "wireless" has become a generic and all-encompassing word used to describe communications in which electromagnetic waves or RF (rather than some form of wire) carry a signal over part or the entire communication path. GPS allows drivers of cars and trucks, captains of boats and ships, and pilots of aircraft to ascertain their location anywhere on earth. The term "wireless" came into public use to refer to a radio receiver or transceiver (a dual purpose receiver and transmitter device), establishing its usage in the field of wireless telegraphy early on; now the term is used to describe modern wireless connections such as in cellular networks and wireless broadband Internet. Global System for Mobile Communication (GSM) GSM's air interface is based on narrowband TDMA technology, where available frequency bands are divided into time slots, with each user having access to one time slot at regular intervals. GSM offers a variety of data services. GSM users can send and receive data, at rates up to 9600 bps ISDN, Packet Switched Public Data Networks, and Circuit Switched Public Data Networks using a variety of access methods and protocols, such as X.25 or X.32. A unique feature of GSM, not found in older analog systems, is the Short Message SerA GSM network consists of mobile stations talking to the base transceiver station, on the Um interface. Many BTS are connected to a BSC via the Abis interface and the BSC connect to the MSC (The core switching network) via the A interface. INCON X

3 HLR and VLR provide customized subscriber services and allow seamless movement from one cell to another. The Authentication register and the equipment register provide security and authentication. An OMC and a cell broadcast center allow configuration of the network and provide the cell broadcast service in the GSM network (not shown in the diagram).the voice transmitted on the air interface can be encrypted. GSM Association together with the Universal Wireless Communications. The majority of European GSM operators plan to implement general packet radio system (GPRS) technology as their network evolution path to third-generation. GSM cordless telephony system to provide a small home base station to work with a standard GSM mobile phone in similar mode to a cordless phone. The base station would be connected to the PSTN. GPRS General packet radio service (GPRS) is a packet-based wireless data communication service designed to replace the current circuit-switched services available on the secondgeneration global system for mobile communications (GSM) and time division multiple access (TDMA) IS-136 networks. General packet radio service (GPRS) is a packet orientedmobile data service on the 2G and 3Gcellular communication systems global system for mobile communications (GSM). The service is available to users in over 200 countries worldwide. Services offered GPRS extends the GSM circuit switched data capabilities and makes the following services possible: "Always on" internet access Multimedia messaging service (MMS) Push to talk over cellular (PoC/PTT) Instant messaging and presence wireless village Internet applications for smart devices through wireless application protocol (WAP) Point-to-point (P2P) service: inter-networking with the Internet (IP) INCON X

4 GPRS support nodes (GSN) A GSN is a network node which supports the use of GPRS in the GSM core network. All GSNs should have a Gn interface and support the GPRS tunnelling protocol. Gateway GPRS Support Node (GGSN) The Gateway GPRS Support Node (GGSN) is a main component of the GPRS network. The GGSN is responsible for the interworking between the GPRS network and external packet switched networks, like the Internet and X.25, WiMax networks. The GGSN converts the GPRS packets coming from the SGSN into the appropriate packet data protocol (PDP) format (e.g., IP or X.25) and sends them out on the corresponding packet data network. In the other direction, PDP addresses of incoming data packets are converted to the GSM address of the destination user. The readdressed packets are sent to the responsible SGSN. serving GPRS Support Node (SGSN) A Serving GPRS Support Node (SGSN) is responsible for the delivery of data packets from and to the mobile stations within its geographical service area. Its tasks include packet routing and transfer, mobility management (attach/detach and location management), logical link management, and authentication and charging functions. The packet data protocol (PDP; e.g., IP, X.25, FrameRelay) context is a data structure present on both the Serving GPRS Support Node (SGSN) and the Gateway GPRS Support Node (GGSN) which contains the subscriber's session information when the subscriber has an active session. When a mobile wants to use GPRS, it must first attach and then activate a PDP context. This allocates a PDP context data structure in the SGSN that the subscriber is currently visiting and the GGSN serving the subscriber's access point. The data recorded includes Subscriber's IP address Subscriber's IMSI Scope Theory of mobile communications, mobile technology, and mobile commerce applications.mlearning is the term referencing the potential for educators considering change in global conversation using mobile communication.mobilearn 2006 conference, mobile communication is ever increasingly becoming part of internet enabled INCON X

5 Web 2.0 conversation. Synchronous chat boards such as MSN and Yahoo us t is interesting how these technologies are being considered by educators and students alike.by younger generations ( generation C) are becoming mobile enabled. n the case of SMS ( Short Messaging Service) the architecture of mobility demands short, sharp and often confusing interaction. In some areas of the world SMS messaging is one of the largest and growing areas of electronic information transaction. Advantages Mobile phones have many advantages. Some of these advantages include: To call different services in case of an emergency. * To contact people who may not have access to a landline. * To keep in touch with people regardless of where they are. This section focuses on the advantages from two kinds of wireless mobile learning, mlearning as a form of performance support and m-learning as communication that creates knowledge Disadvantage A raging and very relevant issue is also the health risks associated with using mobile communication technology. Lack of Well-Developed Metacognitive Skills. Small Screens and Difficulty Accessing Information from the Web. Security is a challenge in the office environment with desktop PCs, and that challenge is magnified with mobile devices. Because of their size and portability, they are easy to lose, subject to damage, and more likely to be stolen the systems. Discussion and Conclusion Mobile technology, mobile Internet access, and m-commerce are growing rapidly on the global stage; however, growth rates vary widely across economic regions. The penetration rate of mobile phones, the optimum combination of different generations of telecommunications, and the combination of different technical formats vary according to a wide array of economic, sociocultural, and policy-related factors. The ways in which companies integrate m-commerce applications into their business models depend upon numerous environmental factors, particularly the combination of communications technologies previously adopted and the mobile technologies currently diffusing in their domestic economies. Given the scope for technological leapfrogging and alternative national mixes of fixed lines and wireless infrastructures, global heterogeneity in national patterns of m-commerce development and hence, of business models in m-commerce appears to be a likely prospect for the foreseeable near future. An interesting consequence of this global heterogeneity is the tenuousness of the distinction between "leading" and "lagging" countries. Nations that "lag" in fixed-line telephony or Internet use stand to benefit proportionately more from mobile technologies and may, in some cases, be better positioned to innovate their use; though it is always dangerous to speculate, there is some indication that industrialized East Asian countries may fall into this category INCON X

6 References: [1] T. Rappaport, Wireless Communications: Principles and Practice,2nd ed., (Upper Saddle River, N.J.: Prentice Hall, 2002). [2] A. Molisch, Wireless Communications, (Chichester, UK: IEEE press - John Wiley, 2005). [3] A. Goldsmith, Wireless Communications, (New York: Cambridge University Press, 2005). [4] Code of Federal Regulations, Title 47. [5] W.C.Y. Lee, Lee s Essentials of Wireless Communications, (New York: McGraw-Hill, 2001). [6] W.C.Y. Lee, Wireless and Cellular Communications, 3 rd Ed., (McGraw Hill, Oct 2005). [7] V.K. Garg, Wireless Communications and Networking, (San Francisco: Morgan- Kaufmann, 2007). [8] J.G. Proakis, Digital Communications, 4 th Ed., (McGraw Hill, Dec 2001). ***** INCON X