Analogy of Promising Wireless Technologies on Different Frequencies: Bluetooth, WiFi, and WiMAX Sanjeev Dhawan Faculty of Computer Science & Engineering, University Institute of Engineering and Technology (U.I.E.T), Kurukshetra University Kurukshetra (K.U.K)-136118, Haryana, India [email protected] Abstract The explosive growth of the Internet over the last decade has led to an increasing demand for highspeed, ubiquitous Internet access. Broadband Wireless technologies are increasingly gaining popularity by the successful global deployment of the Wireless Personal Area Networks (Bluetooth- IEEE 802.15.1), Wireless Local Area Networks (WiFi- IEEE 802.11n), and Wireless Metropolitan Area Networks (WiMAXIEEE 802.16). New ICT and e-Learning strategies and advances in Wireless standards and technologiesparticularly in the areas of Bluetooth, WiFi (Wireless Fidelity), WiMAX (Worldwide Interoperability for Microwave Access) and mobile computing can help to bridge the digital divide in education and research. Using open broadband Wireless technologies and implementing mobile computing architectures, one can overcome the challenges of ground, infrastructure, and finance to increase access; deploy broadband quickly and cost-effectively to areas currently not served; and extend the benefits of digital revolution to previously unreachable populations. These technologies aim to provide low-cost, high-performance Wireless access to residential and business applications. As technology evolves to address portable and mobile applications, the required features and performance of the system will increase. Evolution toward the phase called “full mobility” provides incremental support for low latency, low packet loss and real-time handoff of subscriber terminals operating at high speeds. This paper presents the analogy of promising Wireless technologies on different frequencies: Bluetooth, WiFi, and WiMAX. This paper is organised into four parts: part I describes the functionality and usage of Bluetooth in the Wireless Personal Area Networks, part II presents the WiFi- IEEE 802.11n strategies for users considering higher-bandwidth alternatives to existing Wireless Personal Area Networks, part III discusses how the WiMAX is used as a current standard for Wireless data transmission technology, which is optimized to deliver high, bursty data rates to mobile subscribers, and to support real-time multimedia and Voice over IP (VoIP) applications, and part-IV explores how these emerging Wireless technologies differ from one another. Key Words: Bluetooth, WiFi, WiMAX. 1. Introduction Increased use of mobile devices within the organization, and increase in worker mobility, has fuelled the demand for Wireless networks. Wireless technology is a patchwork of incompatible systems. Initially, the technology was slow, expensive and reserved for mobile situations or hostile environments, where cabling was impractical or impossible. With the maturing of industry standards and the deployment of lightweight Wireless devices alter the need of hardware-software co-design to overcome the problems of present Wireless scenario. Wireless technology has come of age, which enables two or more computers to communicate using standard network protocols. Wireless networking does not require any fixed infrastructure and cabling. This technology is propelled the emergence of cross-vendor industry standards such as IEEE 802.11 and IEEE 802.16 This technology has produced a number of affordable Wireless solutions that are growing in popularity with the organizations for sophisticated applications, where more mobility is required. This will comprise most of the recent Wireless technologies that are in use. There are three kinds of Wireless networks: (a) An ad-hoc, or peer-topeer Wireless network, which consists of a number of computer systems, each equipped with a Wireless networking interface card. Each system can communicate directly with all of the other Wireless The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007) 0-7695-2842-2/07 $25.00 c 2007 enabled computers via Wireless Personal Area Networks (Bluetooth). They can share files and printers through this mechanism; (b) In WiFi technology, a Wireless network can also use an access point, or base station. In this type of network the access point acts like an active hub to provide Wireless connectivity between the computers. It can be connected through the bridges or routers; and (c) In WiMAX technology was formed in June 2001 to promote conformance and interoperability on the IEEE 802.16 standard. In this type of network the technology supports speeds as high as 70Mbps and a range of up to 48 kilometers. WiMAX can be used for Wireless networking like the popular WiFi. WiMAX allows higher data rates over longer distances, efficient use of bandwidth, and avoids interference almost to a minimum. With high performance in both distance and throughput, WiMAX technology could be a new harbinger to current Internet providers seeking to become the leader of next generation Wireless Internet access. Fig. 1 Types of Wireless network technology access. More than one billion people can connect to the Internet and take advantage of its broad array of information-rich experiences. The remaining 5.5 billion people, however, do not have access to computers or the Internet. This “digital divide”- the gap between those who benefit from ICT and those who cannot- has been attributed most commonly to socio-economic factors, affecting developing countries disproportionately. Africa, for example, accounts for about 14 percent of the world’s population, but only 3.6 percent of its population can connect to the Internet. In contrast, North America makes up about 5 percent of the world’s population and 69 percent of its population has access to the Internet [1], [2]. Work is happening on most of these technologies to bring out applications so that they really help everyone stay connected. Some of the technologies are already available, while others might be available towards the end of this year or the beginning of the next year. The types of various Wireless network technologies options are shown in figure 1. In the present paper, an attempt has been made to describe the basic nature of existing Wireless technologies and their applications for implementing brighter technology solution for the educational, research, and business sectors. 2. Bluetooth technology Bluetooth is a technology where all the mobile devices are connected when the other device comes in the range of one mobile device. It was developed to be used for mobile computing devices, such as laptops or mobile phone, in LANs, but is now increasingly used for more services 2.1 Working and existing range for Bluetooth The coverage area of Bluetooth dongle is from 20 feet to 15 meter. The actual distance varies depending upon the environment: manufacturers typically state both indoor and outdoor ranges to give a reasonable indication of reliable performance. Also it should he noted that when operating at the limits of range the performance may drop, as the quality of connection deteriorates and the system compensates. Bluetooth connections are automatic and almost instantaneousfaster than pulling and connecting a cable. Bluetooth can eliminate cables between personal devices. You can connect your notebook computer or PDA, for example, to your cell phone and use it as a modem. Unlike WiFi, Bluetooth includes service discovery and usage profiles. These devices automatically make the right servicesuch as a printer offering a printing service to phoneavailable once connected. Moreover, Bluetooth operates at lower power levels than 802.11, with many devices transmitting at just 1 or 10 Milli-Watts, and is aimed at ad hoc connectivity. The Bluetooth specification is controlled by the Bluetooth special interest group and is a standard, IEEE 802.15.1. The Bluetooth connections are based on piconets. A piconets includes a master device and up to seven slave devices. An additional 254 devices can be in a parked state waiting to join the piconet. The user’s device intimating the communication on the frequencyhopping sequence. Bluetooth uses spread-spectrum radio in the 2.4 GHz band (as do 802.11b and 802.11g) based on frequency hopping. Distinguishing and isolating one piconet (laptop to cell phone connection, for example) from another (say, your cell phone to headset connection) is the frequency-hopping sequence. The connection speed can be as high as 721 Kbps in one direction and 57.6Kbps the other way in an asymmetrical configuration, or 432.6 Kbps in each direction in a symmetrical configuration. A piconet also support three full-duplex voice channels at Metropolitan Area Network (WiMAX- IEEE 802.16) Local Area Network (WiFi- IEEE 802.11) Wireless Personal Area Network (Bluetooth) The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007) 0-7695-2842-2/07 $25.00 c 2007 Fig. 2 Profile set of working Bluetooth protocols. Object Exchange (OBEX) (Simple client- server protocol from IRDA) IP PPP AT-commands (control) Other protocols Optional Bluetooth protocols RFCOMM (emulates serial port) Telephony control service (Voice not over IP) Logical Link Control and Adaptation Control Protocol (L2CAP) (multiplexes different traffic types and provide QoS) Service Discovery Protocol (SDP) (scans for other devices, shares information about profiles and applications) ( Core Bluetooth protocols Link Management Protocol (LMP) (handles authentication) Circuit Switched or Packet Switched Services Radio Source: Bluetooth specifications 64Kbps. These speeds are fine for modem connections, voice communications, synchronizing PDAs, and retrieving low and medium resolution digital images, but not fast enough for peripherals, such as digital video cameras. A profile set of working Bluetooth protocols and their capabilities are mentioned in the figure 2, which is used to provide a well defined service-SPP (serial port profile), dial-up networking, headset, hands free, LAN access, fax profile, file transfer and synchronization [3]. 2.2 Technical Feasibility and device requirement for Bluetooth Devices Bluetooth technology does not require any hub or switch for communication. Here every node has some finite area then the other node can work as router/ gateway itself. The Bluetooth technology basically works on the following core Bluetooth protocols viz. logical link control and adaptation control (L2CAP), link management protocol (LMP). Table1. Bluetooth technology specifications Sr. no Requirement for Bluetooth technology 1 Bluetooth Adapter/Dongle 2 Laptop/ Desktop with Bluetooth 3 Mobile Phone with Bluetooth 3. WiFi (Wireless Fidelity)– IEEE 802.11n WiFi is a brand originally licensed by the WiFi alliance to describe the underlying technology of Wireless Local Area Networks (WLAN) based on the IEEE 802.11 specifications. It was developed to be used for mobile computing devices, such as laptops, in LANs, but is now increasingly used for more services, including Internet and VOIP phone access. Demand for Wireless LAN hardware has experienced an exceptional growth during the past several years, evolving quickly from innovation into necessity. WiFi technology is most commonly found in notebook computers and Internet access devices such as routers and DSL or cable modems. The growing frequency of The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007) 0-7695-2842-2/07 $25.00 c 2007 WiFi is helping to extend the technology beyond the PC and into consumer electronics applications like Internet telephony, music streaming, gaming, and even photo viewing and in-home video transmission. These new uses, as well as the growing number of conventional WLAN users, increasingly combine to strain existing WiFi networks [7] [8]. The industry has come to an agreement on the components that will make up 802.11n, a new WLAN standard that promises both higher data rates and increased reliability. A Wireless LAN (WiFi) is a data transmission system designed to provide location-independent network access between computing devices by using radio waves rather than guided medium. WiFi is meant to be used for referring any type of 802.11 network, whether 802.11b, 802.11a, 802.11g etc. The first 802.11b networks could move data at up to 11 megabits per second (Mbps). Then came products using 802.11a, followed shortly thereafter by 802.11g, each with maximum speeds of 54Mbps and throughput of around 25Mbps. WLAN hardware built around 802.11g was quickly embraced by consumers and businesses seeking higher bandwidth. The next WiFi speed standard, 802.11n, will likely offer a bandwidth of around 108Mbps. 3.1 Range Feasibility for WiFi Each access point in WiFi has a finite range within which a Wireless connection can be maintained between the client computer and the access point. The actual distance varies depending upon the environment: manufacturers typically state both indoor and outdoor ranges to give a reasonable indication of reliable performance. Typical indoor ranges are 150-300 feet. But can be shorter if the building construction interferes with radio transmissions. Longer ranges are possible; but performance will degrade with distance. Outdoor ranges arc quoted up to 1000 feet. But again this depends upon the environment conditions. 3.2 Devices requirements for WiFi technology Table2. WiFi technology specifications Sr. No. Requirement for WiFi technology 1. Laptop /Desktop/PDA 2. 802.11a Adapter for Desktop/Laptop 3. 802.11b Adapter Desktop/Laptop 4. 802.11g Adapter Desktop/Laptop 5. 802.11a/b/g Access Point (Indoor) 6. 802.11a/b/g Access Point (Outdoor) 7. 802.11a/b/g Wireless Switch 8. 802.11a/b/g Dongle USB Port 9. Wireless Media Player 10. Wireless Gateway 11. Antenna Indoor and Antenna Outdoor 12. Wireless Bridge 13. Wireless Camera 14. Range Booster 3.3 Existing Use of WiFi A person with a WiFi enabled device such as a computer, cell phone or PDA can connect to the Internet when in proximity of an access point. The region covered by one or several access points is called a hotspot. Hotspots can range from a single room to many square miles of overlapping hotspots. WiFi can also be used to create a mesh network. Both architectures arc used in community networks. WiFi also allows connectivity in peer-to-peer (Wireless adhoc network) mode, which enables devices to connect directly with each other. This connectivity mode is useful for consumer electronics and gaming applications. When the technology was first commercialized, there were many problems because consumers could not be sure that how the products from different vendors would work together. The WiFi alliance began as a community to solve this issue so as to address the needs of the end user and allow the technology to mature. The Alliance created the branding WiFi certified to show consumers that predicts are interoperable with other products displaying the same branding. Home WiFi infrastructure devices typically fall into the category of a multifunction piece of networking equipment, with Wireless being only one of many features. Home WiFi clients come in many shapes and sizes, from stationary PCs to digital cameras. The trend today and into the future will be to enable Wireless into every device where mobility is prudent. WiFi devices are often used in home or consumer-type environments in the following manner: Termination of a broadband connection into a single router, which services both wired and Wireless clients, ad-hoc mode for client-toclient connections, built into non-computer devices to enable simple Wireless connectivity to other devices or the Internet. The current technology trends in the corporate Wireless world are: Dramatically increasing the number of WiFi Access Points in an environment, in order to provide redundancy and smaller cells, designing for Wireless voice applications (VOWLAN or WVOIP), moving toward ‘thin’ Access Points, with all of the intelligence housed in a centralized network appliance: relegating individual Access Points to the simply ‘dumb’ radios. Outdoor applications utilizing true mesh topologies, a proactive, self-managed network that functions as a security gateway, firewall. DHCP server, intrusion detection system, and a myriad The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007) 0-7695-2842-2/07 $25.00 c 2007 of other features not previously considered relevant to a Wireless network. 3.4 Technical information and working flow of WiFi A typical WiFi setup contains one or more Access Points (APs) and one or more clients. An AP broadcasts its SSID (Service Set Identifier, “Network name”) via packets that are Called beacons, which are usually broadcast every 100 ms. The beacons arc transmitted at 1 Mbit/s, and are of relatively short duration and therefore do not have a significant effect on performance. Since 1 Mbit/s is the lowest rate of WiFi, it assures that the client who receives the beacon can communicate at least 1 Mbit/s. Based on the settings (e.g. The SSID). The client may decide whether to connect to an AP. If two APs of the same (SSID) are in range of the client, the client firmware might use signal strength to decide which of the two APs to make a connection. The WiFi standard leaves connection criteria and roaming totally open to the client. This is a strength of WiFi, but also means that one Wireless adapter may perform substantially better than another. Since WiFi transmits in the air. It has the same properties as a non-switched wired Ethernet network, and therefore collisions can occur. Unlike a wired Ethernet, and like most packet radio, the WiFi cannot do collision detection, and instead uses a packet exchange (RTS/CTS used for Collision Avoidance or CA) to try to avoid collisions channels. 3.5 Use of Standard Devices in WiFi 3.5.1 Wireless Access Point (WAP) A Wireless access point connects a group of Wireless devices to an adjacent wired LAN. An access point is similar to an Ethernet hub, relaying data between connected Wireless devices in addition to a (usually) single connected wired device, and most often an Ethernet hub or switch, allowing Wireless devices to communicate with other wired devices. 3.5.2 Wireless Adapter A Wireless adapter allows a device to connect to a Wireless network. These adapters connect to devices using various interconnects such as PCI, USB, and PCMCIA. 3.5.3 Wireless Router A Wireless router integrates a Wireless Active Protocol (WAP, Ethernet switch, and internal Router firmware application that provides IP Routing. The DNS forwarding through an integrated WAN interface. A Wireless router al1ows wired and Wireless Ethernet LAN devices to connect to a (usually) single WAN device such as cable modem or DSL modem. A Wireless router allows all three devices (mainly the access point and router) to be configured through one central utility. This utility is most usually an integrated web server which serves web pages to wired and Wireless LAN clients and often optionally to WAN clients. This utility may also be an application that is run on a desktop computer such as Apple’s airport. 3.5.4 Wireless Ethernet Bridge A Wireless Ethernet bridge connects a wired network to a Wireless network. This is different from an access point in the sense that an access point connects Wireless devices to a wired network at the data-link layer. Two Wireless bridges may be used to connect two wired networks over a Wireless link. Useful in situations where a wired connection may be unavailable, such as between two separate homes. 3.5.5 Range Extender A Wireless range extender or Wireless repeater can extend the range of an existing Wireless network. Range extenders can be strategically placed to extend a signal area or allow the signal area to reach around every corner of the building. Wireless devices connected through repeaters will suffer from an increased latency for each hop. Additionally, a Wireless device at the end of chain of Wireless repeaters will have a throughput that is limited by the weakest link within the repeater chain. Antenna connectors’ and most commercial devices (routers, access points, bridges, repeaters) designed for home or business environments use either RP-SMA or RP-TNC antenna connectors. PCI Wireless adapters also mainly use RP-SMA connectors. 4. WiMAX: IEEE 802.16 standard Yet another Wireless network technology may have an impact over the next few years: 802.16, better known as WiMAX. The IEEE approved the 802.16 standards in June 2004. This technology supports speeds as high as 70Mbps and a range of up to 48 kilometers. WiMAX can be used for Wireless networking like the popular WiFi. WiMAX allows higher data rates over longer distances, efficient use of bandwidth, and avoids interference almost to a minimum. WiMAX can be termed partially a successor to the WiFi protocol. Current technologists envision a WiMAX receiver in a person’s home, with a WiFi transmitter to serve in-home connections, and longer term having laptops and personal devices capable of The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007) 0-7695-2842-2/07 $25.00 c 2007 transmitting directly to WiMAX towers. The IEEE 802.16 Forum describes WiMAX as “a standardsbased technology enabling the delivery of last mile Wireless broadband access as an alternative to cable and DSL.” The bandwidth and reach of WiMAX make it suitable for the following potential applications: connecting Wi-Fl hotspots with each other and to other parts of the Internet, providing a Wireless alternative to cable and DSL for last mile (last km) broadband access, providing high-speed mobile data and telecommunications services, and Providing a diverse source of Internet connectivity as part of a business continuity plan. If a business has a fixed and a Wireless Internet connection, especially from unrelated providers, they are unlikely to he affected by the same service outage. Typically, in WiMAX each cell has a whole 100 Mbps backhaul so there is no contention here. In practice, many users will have a range of 2-. 4-. 6-, 8- or 10Mbps services and the bandwidth can be shared. It is easy to predict capacity requirements as you add customers and additional radio cards can be added on the same sector to increase the capacity. Some cellular companies are evaluating WiMAX as a means of increasing bandwidth for a variety of dataintensive applications; indeed, Sprint Nextel has announced in mid-2006 that it will be investing about US$ 3 billion in a WiMAX technology to build it out over the next few years. In line with these possible applications is the technology’s ability to serve as a high bandwidth “backhaul” for Internet or cellular phone traffic from remote areas back to an Internet backbone. Although the cost-effectiveness of WiMAX in a remote application will be higher. It is not limited to such applications, and may be an answer to reducing the cost of TI/El backhaul as well. Given the limited wired infrastructure in some developing countries, the costs to install a WiMAX station in conjunction with an existing cellular tower or even as a solitary hub are likely to be small in comparison to developing a wired solution. Areas of low population density and flat terrain are particularly suited to WiMAX and its range. For countries that have skipped wired infrastructure as a result of prohibitive costs and unsympathetic geography, the WiMAX can enhance Wireless infrastructure in an inexpensive, decentralized, deployment- friendly and effective manner. The 802.16-2005 standard supports the frequency range of 2 to 6 GHz, although other frequency bands can also be accommodated. Figure 3 shows the various frequency bands available around the world. It is anticipated that additional frequency bands on a regional basis will also be auctioned. WiMAX operates in a mixture of licensed and unlicensed bands. The unlicensed bands are typically the 2.4 GHz and 5.8 GHz bands. Licensed spectrum provides operators control over the usage of the band, allowing them to build a high-quality network. The unlicensed band, on the other hand, allows independents to provide backhaul services for hotspots. In this paper, 3.5 GHz and higher are defined as higher frequency bands. Currently, significant activity is underway in the 2.5 GHz and 3.5 GHz bands. Fig. 3 Frequencies available for WiMAX deployments around the World. 4.1 Technical Information for WiMAX WiMAX is a term coined to describe standard, interoperation implementations of IEEE 802.16 Wireless networks, in a rather similar way to WiFi being interoperable implementations of the IEEE 802.11 Wireless LAN standard. However, WiMAX is very different from WiFi in the way it works. Table 4. Devices requirement for WiMAX Sr. No. Requirement for WiMAX technology 1 License for particular frequency 3.5GHz/5.8GHZ 2 802.16 Adapter for Desktop/Laptop 3 Wireless Gateway and Wireless Bridge 4 Antenna Indoor and Antenna Outdoor 5 Laptop /Desktop 4.2 Characteristics and system consideration of WiMAX Technical aspects of 802.16a that are instrumental in powering robust performance include following characteristics: Power: Varies with band. Profiles from 100 MW up to 2W, Configuration: P-P and P-MP Cellular, Spectrum: Initially 3.5 GHz licensed and 5.8 GHz unlicensed bands, Radio interface: OFDM, using 256 tones, Access Protocols: Downstream - TDM Spectrally agile systems may be required as new spectrum becomes available in regions around the world (e.g. 700 MHz, 1700 MHz). The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007) 0-7695-2842-2/07 $25.00 c 2007 (Broadcast), Upstream TDMA with access contention, Security via station authentication and encryption, Data rates variable with channel bandwidth 3.5 MHz in 3.5 GHz band, 20 MHz in 5.8 GHz band, Actual realizable data rates are ~ 2b/Hz, and Maximum range ~ 2Km for indoor Non-LOS cellular service at 3.5 GHz. The 802.16-2005 standard will introduce the OFDMA (Orthogonal Frequency Division Multiplex Access) method and MIMO (Multiple Input Multiple Output) antenna technology [4] [5]. One of the major advantages of OFDM is its extreme robustness in multi-path environments. The basic operating principle for OFDM is as follows: (a) A transmit channel is divided into a large number of parallel sub-channels (N>>1), (b) The data stream from the source is split into each sub-channel, (c) Consequently, the data rate of each sub-channel becomes 1/N of the main string and the symbol duration becomes N times longer, and (d) Each sub-channel is transmitted via a very narrow bandwidth so the signal fading is basically flat within the sub-channel. As a result, the longer symbol duration and flat fading make OFDM robust under multi-path fading with no inter-symbol interference. Combining advanced MIMO antenna technology for data transmission with OFDM enables a number of key operational benefits that can translate into significant cost savings and advantages, namely: powerful spectral efficiency and throughput, gains, More efficient utilization of power- for the same power output per sector, MIMO provides greater capacity with the same coverage as single output systems, higher reliability and throughput. The system supports adaptive modulation in the downlink and uplink. Modulations ranging from BPSK 1/2 to 64QAM 3/4 may be employed. Adaptive modulation techniques, such as monitoring link quality between the transmitter and receiver and selecting the highest usable data rate, are used throughout the product range [9] [10] [11]. Path loss, dB Fig. 4 Cell radius vs. path loss. In perspective to WiMAX deployment there are certain impact of frequency band on range link budget and path loss. Therefore, the importance of considering path loss, shadow margin and physical environment when developing a link budget to design for optimal range and coverage. Figure 4 shows a comparison of coverage versus path loss at different frequency bands. This example assumes a link budget of 142 dB, which provides a cell radius of 3 km in the 1900 MHz band. 4.3 Advantages over WiFi The WiMAX specifications provide symmetrical bandwidth over many kilometers and range with stronger encryption (3DES or AES) and typically less interference. WiFi is short range (approximately l0’s of meters) and suffers from interference as in metropolitan areas where there are many users; WiMAX is focused on licensed spectrum. Availability varies by country: most available spectrum is in 2.3 GHz-2.7 GHz and 3.4-3.7 GHz ranges. Total available spectrum varies from 40 to over 200 MHz depending on regulations, WiFi hotspots are typically backhauled over ADSL in most coffee shops therefore WiFi access is typically highly contended and has poor upload speeds between the router and the internet. It provides connectivity between network endpoints without the need for direct line of sight in favorable circumstances, and the 802.16 specifications apply across a wide range of the RF spectrum. The most likely bands used will be around 3.5G Hz. 2.3/2.5GHz or 5GHz. The actual radio bandwidth of spectrum allocations is also likely to vary. 5. A case study 1: satellite link for EduSat in India EduSat, an initiative funded by the Indian Space Research Organization (ISRO), focuses on improving access to the Internet and delivering education-focused Internet services with an innovative two-way “Internet via satellite” network to remote Indian schools (see Figure 5). The project provided small satellite dishes to primary schools in areas poorly served by broadband. The local authority had difficulty in facilitating Internet access requirements for the schools in this region and decided that a satellite service could play an important role in meeting these needs. The ISRO implemented the satellite infrastructure and set up a multicasting service that pushed selected educational content from a number of leading sources. Caching the content on a server at each school provided local access for students and teachers, which enabled a rich media learning experience. For interactive tasks, such as filling out questionnaires and online research, users could access Cell radius, km The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007) 0-7695-2842-2/07 $25.00 c 2007 the Internet through the satellite link. Using satellite technology for this type of service offers several advantages: gives schools fast access to the Internet, can be installed in any school regardless of location, can be installed quickly- on average equipment setup at each school took half a day, provides a secure, managed network for schools, gives stakeholders a system capable of pushing specific Web-based content and digital resources to all schools instantly, can be integrated with other compatible services where such services exist. Plans are currently underway for implementing multicast broadband over WiMAX technology as the next phase to this project. Fig. 5 EduSat technology overview. 6. A case study 2: spectral considerations at 3.5 GHz Nortel is partnering with the Alberta Special Areas Board (SAB) and Netago Wireless to build Canada’s first commercial WiMAX network at 3.5 GHz in Canada, and recently completed a live-air trial. The main goal of the trial was to determine the performance, configuration and operation of the technology. Tests were performed to determine data rates, signal-to-noise ratio, modulation rate, received signal strength indicator, transmit power and range. Two types of schemes were used: an outdoor unit with 15 dB antenna gain and maximum transmit power of 23 dB and an indoor unit with a 6-7 dB antenna gain with a maximum transmit power of 24 dB. Data throughput performance using UDP, TCP and FTP protocols were tested in the down and up links. The trial measured 9 Mbps data throughput using UDP and 5 Mbps using FTP/TCP. Figure 6 depicts the range and data rate performance carried out by Nortel. This case study highlights that WiMAX networks can be successfully deployed at 3.5 GHz and it becomes even more important when deploying mobile WiMAX networks [6]. Fig. 6 The IEEE 802.16-2004 trial results of Nortel. 7. Comparison of Wireless technologies The use of Wireless technologies is beginning to appear similar to the initial development of the railways. Each technology seems to have a different “gauge” and compatibility issues seem to confuse the novice. The main points of comparison of the three technologies that have been discussed in this paper are listed in table 4. Table 4. Comparison of emerging Wireless technologies Technology Bluetooth WiFi - 802.11n WiMAX Application Personal Area Network Wireless LAN, Internet Broadband Internet connectivity Typical Range 5-20 m 100m 50 km Frequency Range 2.4- 5 GHz 2.4 GHz 2-11GHz Data Rate 2-6 Mbps 54-108 Mbps 75 Mbps Modulation TDM DSSS QAM Network IP & P2P IP & P2P IP IT Network Connectivity NO Yes Yes Network Topology Infrastruct -ure Infrastructure (Ad-hoc also possible) Infrastructure Access Protocol L2CAP/ LMP CSMA/CA Request/Grant Key Attributes Less cost Wider Bandwidth, Flexibility Throughput, Coverage 8. Conclusions This paper has presented an overview of emerging Wireless technologies. Bluetooth is a The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007) 0-7695-2842-2/07 $25.00 c 2007 capable, well designed Wireless technology, but it doesn’t address high bandwidth PAN needs, such as transferring high resolution video images, music files, video data, nor synchronizing large personal databases, and also having security threats. Therefore, the Bluetooth is likely to make best use of its low power and low speed operation in short-range equipment interconnects, such as personal computers and portable equipment. The WiFi-802.11n is viewed as being superior in maintaining compatibility with existing Wireless LAN, while Bluetooth is generally thought more likely to achieve lower levels of power consumption. 802.11n is viewed as the most likely contender for the home network backbone. Our vision of the future is that WiMAX will enable mobile broadband at an affordable price. This will be achieved through the adoption of WiMAX by a cellular provider seeking to make a jump to this disruptive technology. WiMAX is not expected to completely eliminate the WiFi technology in the near future, but will be a complement to WiFi as its primary backhaul service of choice. WiMAX promises to help corporations expand business, drive down costs, increase overall profitability, increase the quality of service, and increase the number of users that connect to the Internet. Moreover, the mobile WiMAX technology is designed to provide high-quality, mobile broadband multimedia services; however, it presents challenges that operators need to consider before setting up their networks. 9. References [1] Global Challenges Facing Humanity, The Millennium Project: Global Futures Studies & Research. American Council for the United Nations University (AC/UNU) 2006. http://www.acunu.org/millennium/Global_Chall enges/chall-06.html 2. [2] World Internet Usage Statistics- News and Population Stats, Miniwatts Marketing Group. 2001 - 2006.http://www.internetworldstats.com/stats.ht ml. [3] Brush up on Bluetooth, peter Rysavy, www.cmpreprints.com, 2004. [4] Multiple Antenna Technology in WiMAX systems, Atul Salvekar, Sumeet Sandhu, Qinghua Li, Minh-ANh Vuong, Xiaoshu Intel Technical Journal, Volume 8, Issue 3, 2004. [5] OFDM Wireless LAN: A theoretical and practical consideration, Heiskala, J. Terry, SAM 2002. [6] Considerations for deploying mobile WiMAX at various frequencies, Nortel. www.nortel.com. [7] Introduction to Wi-Fi technology, Retrieved on September 24, 2006, www.wi-fitechnology.com [8] Broadcom, 802.11n: Next-Generation Wireless LAN Technology, White paper, April 2006. [9] Emerging Wireless Standards - WiFi, ZigBee & WiMAX, Bhavneet Sidhu, Hardeep Singh, and Amit Chhabra, Transactions on Engineering, Computing and Technology, World Enformatika Society, Vol. 19 January 2007, pp308-13. [10] WiMAX End-to-End Network system architecture: NWG network specification, WiMAX Forum, White paper, April 20, 2005. [11] Westech Communications Inc. on behalf of the WiMAX Forum, Can WiMAX Address Your Applications? White paper, Oct. 24,2005. The 2nd International Conference on Wireless Broadband and Ultra Wideband Communications (AusWireless 2007) 0-7695-2842-2/07 $25.00 c 2007 -- http://www.wretch.cc/blog/chenkobe --

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