Wireless technology - Essay Example

This paper defines VoIP, explores the better known available wireless technologies, and explains the advantages and disadvantages of each technology in delivering this new service. Introduction Voice over Internet Protocol (VoIP), is a technology that allows a user to make telephone calls using a broadband Internet connection instead of an analogue phone line: FCC The following diagrams illustrate various implementations of VoIP: PC to Analogue telephone PC to PC Analogue phone to Analogue phone1 VoIP not only offers savings of between 20 to 50 percent depending on the service and calling needs but also offers feature-rich services, such as those usually found only on high-end phone systems, eg call routing and voicemail-to-email integration and some that are designed to operate over excess cable-modem or DSL bandwidth such as Instant Messaging and video calls. Businesses are particularly interested in VoIP's affordability, flexibility and the ability to upgrade via software. They also like its potential for tight integration with email and Web-based services for applications such as call centres, videoconferencing, and click-to-talk Web pages. Many of these features are migrating to consumer customers. For example, most consumer videoconferencing technology uses the same SIP protocol used by VoIP. One difficulty will always remain in such solutions: VoIP is only as reliable as your broadband connection. If there is a power outage or a dropped connection the VoIP is lost. For most users then a contingency plan will be required if they are using any of the above schema. Going wireless The configurations presented above assume that the user will be in reach of a landline or a computer. Yet in the same way that people have discarded their landlines in favour of cellular telephones, it is envisaged that people will want to retain the freedom of a cellular, but at lower VoIP call rates. What's really required by the WiFi generation is a 'roaming' solution that has the convenience of WiFi, the coverage of a cellular network with a Bluetooth 'hands-off' package. We now examine some of the wireless technologies and see what they can offer in terms of VoIP. Bluetooth Bluetooth is a low-cost wireless communications technology that links devices such as mobile phones, laptop and printers to a short-range wireless, personal area network. Bluetooth technology operates on 2.4GHz, the same bandwidth as WiFi. Bluetooth wireless can transmit data up to a rate of 1 Mbps, or 2 Mbps in the second generation of the technology. There has been talk of Bluetooth technology losing momentum as WiFi, Ultrawideband (UWB), and other networking technologies take off. But Bluetooth SIG believes the technologies serve different functions and ultimately will work together. The key difference between Bluetooth wireless technologies and other technologies, such as UWB, Wi-Fi and Infrared are range, power consumption and intended use. Bluetooth wireless technology in its most common implementations has a range of 30 feet (10m), is low-power consuming, designed for battery operated mobile devices and provides voice, data and audio connections between devices. Infra-red Infrared or IrDA is a well-known technology. It uses pulses of non-visible light to communicate between two devices, such as a remote control to a television or DVD player. One drawback of IrDA is that there must be a clear line of sight between the two devices, and the other disadvantage is that IrDA normally only operates between two devices at a time. Like Bluetooth IrDA has found a niche in connecting devices. Wifi WiFi is short for 'wireless fidelity' and refers to the 802.11b networking protocol for wireless networking. It is a limited-range wireless networking protocol based on the 802.11 family of standards using spectrum in the 2.4 GHz range to exchange data at broadband speeds. The big advantage of WiFi is its simplicity. Devices can be connected without the need for wires. The devices connect to the network using radio signals, and can be up to 100 feet or so apart. If the local area network is connected to the Internet, the Wi-Fi device can have Internet access as well. The access point built into a typical Wi-Fi home router might have a range of 45 m (150 ft) indoors and 90 m (300 ft) outdoors. Disadvantages of Wi-Fi Use of the 2.4 GHz Wi-Fi band does not require a license in most of the world. Hence there is more noise/interference which can cause devices to cease functioning. Power consumption is fairly high compared to other standards, making battery life and heat a concern. 802.11n Also under development is a high-bandwidth extension to the current Wi-Fi standard. The services and protocols specified in IEEE 802 map to the lower two layers (Data Link and Physical) of the seven-layer OSI networking reference model. In fact, IEEE 802 splits the OSI Data Link Layer into two sub-layers named Logical link control (LLC) and Media Access Control, so that the layers can be listed like this: Data link layer LLC Sublayer MAC Sublayer Physical layer Fleishman (2005) expects 802.11n to increase the speed of Wi-Fi connections by 10 to 20 times. Businesses are hoping the technology will allow them to reduce outgoings on Ethernet cabling throughout the building. WiMAX WiMAX stands for 'World Interoperability for Microwave Access' and is a certification mark for products that pass conformity and interoperability tests for the IEEE 802.16e standards. It is engineered to deliver the latest type of fixed and mobile services such as VoIP, Information Technology and Video at very low cost. WiMAX systems are able to cover a large geographical area, up to 50 km and to deliver significant bandwidth to end-users up to 72 Mbps Unlike current Wi-Fi hot spots, which have a reach of about 300 feet, WiMAX stations are able to send and receive signals up to 30 miles away. This makes them ideal for the "last-mile" problem that plagues many areas that are too remote to receive Internet access via cable or DSL. The monthly cost is likely to be less than $50, the average cost today for Internet access via cable or DSL. Although most of the existing wireless technologies suffer from limited range and coverage (usually a few hundred meters around the base station) resulting in very costly combination of technologies (wired and/or wireless), WiMAX technology benefits of a wide coverage and can be deployed as a Point MultiPoint last mile connection but also as part of the backhaul to the PSTN and Internet access points. The WiMAX role in an access network is illustrated in following schema: Following the normal trend of digitalization and packet transmission and switching, WiMAX uses the Internet protocol and thus supports all multimedia services from VoIP to high speed internet and video transmission. Advantages of WiMAX The high speed of broadband service Wireless rather than wired access, so it would be a lot less expensive than cable or DSL and much easier to extend to suburban and rural areas Broad coverage like the cell phone network instead of small WiFi hotspots WiMAX is part of an Internet ecosystem. It is cost effective for a few or for a million subscribers, it is transparent and secure The WiMAX networks will be able to support fixed, nomadic, portable and mobile wireless broadband connectivity on the same network. IEEE 802.16e and 802.20 The downside to WiMax is that it is a "fixed access" system, meaning that customers must mount a dish-like antenna outside their home or office to access it. To get around this, researchers are developing an extension to WiMax called 802.16e. The emerging 802.16e and 802.20 standards will both specify new mobile air interfaces for wireless broadband. On the surface the two standards seem very similar, but there are some important differences between them. For one, 802.16e will add mobility in the 2 to 6 GHz licensed bands, while 802.20 aims for operation in licensed bands below 3.5GHz. The amendment to 802.16 aims to fill the gap between high data rate wireless local area networks (WLAN) and high mobility cellular wide area networks (WAN). The 802.20 interface seeks to boost real-time data transmission rates in wireless metropolitan area networks to speeds that rival DSL and cable connections (1Mbps or more) based on cell ranges of up to 15 kilometres or more, and it plans to deliver those rates to mobile users even when they are travelling at speeds up to 250 kilometres per hour (155 miles per hour). This would make 802.20 an option for deployment in high-speed trains. The 802.16e project authorization request specifies only that it will support subscriber stations moving at vehicular speeds. There is clearly some overlap between the two are not competitive. The IEEE would not ratify a group that has competing interests with an existing group. Ultrawideband An alliance of microchip manufacturers led by Texas Instruments is developing a standard for transmitting large amounts of data over short distances. Dubbed Ultrawideband, (UWB) the technology is intended primarily for in-home use to connect computers and TVs to one another without wires as long as the devices are within 30 feet of one another. In its current restricted state, UWB will most likely be the preferred technology for wireless personal area networks, replacing Bluetooth's 1-2Mbps bandwidth with 400-500Mbps data rates. Conclusion VoIP does have challenges in terms of security, accountability, interoperability and reliability. These areas are outside the scope of this paper, but should be included in a full review of the available wireless technologies for the sake of completeness. On the facts presented here the clear winner seems to be WiMAX which is optimized for multi-media on the move and particularly VoIP. The other technologies are able to offer some functionality in the VoIP sector, but that is not their core revenue earner. WiMAX's range, security, interoperability, standards, data throughput, coverage, cost and ease of configuration cannot be emulated by any of the alternative technologies. References Asaravala, Amit, (2004), Four Wireless Technologies Move Toward Starting Gate, USAToday. Available at: http://www.usatoday.com/tech/wireless/data/2004-03-28-coming-tech_x.htm. Last visited November 17, 2005 Brain, Marshall, ( n.d.), How WiFi Works. Available at http://computer.howstuffworks.com/wireless-network.htm. Last visited November 17, 2005 Fleishman, Glenn, (2005), Broad Consortium Backs Faster Wi-Fi. Available at: http://wifinetnews.com/archives/cat_80211n.html. Last visited November 17, 2005 Geier, J, (2003), A Technology to Consider: Ultrawideband. Available at: http://www.wi-fiplanet.com/tutorials/article.php/1598581. Last visited November 17, 2005 Grabianowski, E and Marshall, B (n.d.), How WiMAX Works. Available at: http://computer.howstuffworks.com/wimax.htm. 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