Small Computer Systems Proposed Research Term Paper
- Length: 15 pages
- Subject: Education - Computers
- Type: Term Paper
- Paper: #43109232
Excerpt from Term Paper :
According to Paul B. Mckimmy (2003), "The first consideration of wireless technology is bandwidth. 802.11b (one of four existing wireless Ethernet standards) is currently the most available and affordable specification. It allows a maximum of 11 megabits per second (Mbps)" (p. 111); the author adds that wired Ethernet LANs are typically 10 or 100 Mbps.
In 1997, when the IEEE 802.11 standard was first ratified, wireless LANs were incompatible and remained vendor specific; the 802.11 protocol representeded an important step towards standardization (Passmore, 2000). Wireless local area network (LAN) technology, however, has actually been in use since the late 1980s; different proprietary approaches were commonly used, and the networks operated at lower speeds (e.g., 1-2 Mbps). In 1997, though, the standards setting body, IEEE, released the 802.(11) standard for wireless local area networking using the unlicensed 2.4 GHz frequency band (as opposed to the 900 MHz band used in the past); this standard was later updated to 802.11b, which increased the transmission speed from 2 to 11 Mbps, or approximately the same transmission speed as traditional wired Ethernet connections. This is the standard that is generally referred to today as Wi-Fi ("wireless fidelity") or wireless LAN (Emerging Technologies, 2002).
Because 802.11a transmits at a different frequency, it remains incompatible with existing Wi-Fi networks; in other words, "new base stations and client cards will be needed. it's likely that vendors will offer dual-standard products, but they are not yet available. It is possible, however, for both standards to co-exist in the same environment" (Emerging Technologies, 2002, p. 6). The incompatibility issue has also resulted in still another revision of the 802.11 standard being proposed; however, this version has not yet been finalized. Currently, 802.11g also operates at 54 Mbps; however, 802.11g runs in the same 2.4 GHz frequency as Wi-Fi thereby providing for retrofitted compatibility with existing Wi-Fi networks. According to the industry analysts at) Language, Learning & Technology, "Stay tuned, since there is yet another new protocol being discussed, 802.11e, which adds QoS ("quality of service") to high-speed bandwidth, guaranteeing a reliable stream of data transmission to individual clients, vital for effective video streaming" (Emerging Technologies, 2004, p. 6).
While vendors continue to seek a mutually compatible protocol in North America, the rest of the world is proceeding at full speed in other directions and a number of other standards for wireless local networks have emerged as well, including Bluetooth and HomePNA (Passmore, 2000). Instead of being a wireless LAN, though, Bluetooth is actually a "personal-area network" (PAN); nevertheless, some analysts expect that it will surpass 802.11 WLANs in popularity. According to Passmore, "Bluetooth is a short-range radio interface for interconnecting many types of devices including mobile phones, PCs, printers, digital cameras, PDAs and devices within automobiles. It is limited to a 10-meter radius and to transmission speeds of only 1 Mbps" (p. 22). Despite these constraints, Bluetooth remains a viable contender in the wireless networking marketplace; this protocol occupies the same 2.4-GHz frequency band as 802.11, and while studies have indicated that the two technologies will be able to coexist as long as they are not in close proximity, simultaneous transmissions may reduce the throughput of each by approximately 25%. Furthermore, this author points out that it might also be technologically impossible to construct a machine that can support both standards, because the device would probably interfere with itself (Passmore, 2000). Although hundreds of vendors had jumped on the Bluetooth bandwagon a few years ago, this technology does not appear to have retained the same level of popularity of the 802.11 series.
For personal use, some potential competitors to 802.11 have included the Home Phone Networking Alliance (HomePNA) and HomeRF standards. For example, Proxim's HomeRF (marketed under the "Symphony" name), combines the 802.11b and the Digital Enhanced Cordless Telecommunications (DECT) portable phone standards into a single system; the latest version (HomeRF 2.0 as of 2004) increments throughput rom 1.6 to 10 Mbps; however, it is also not compatible with Wi-Fi. Based on Intel's recent decision to not support HomeRF, this application's future remains uncertain (Emerging Technologies, 2004). According to Passmore, HomePNA devices were originally designed to allow systems to use the existing wiring for LAN connectivity; however, this retrofitting came at a high price (a rate of 1 Mbps and no mobility); HomeRF was intended to cost less, but poor performance issues have affected its development compared to the already low prices available for the 802.11 protocols, adding to the uncertainty of this protocol's future.
Finally, an IEEE 802.1a standards effort called HiperLAN2 is intended to produce the "next generation" of wireless LAN products (Passmore, 2000). HiperLAN2, developed by Nokia and Ericsson, and approved by the European Telecommunication Standardization Institute (ETSI), is similar to, but like HomeRF, it is not compatible with, 802.11a in that it uses the 5.4 GHz frequency with a throughput of 54 Mbps; however, although 802.11a is primarily a data-delivery protocol, HiperLAN2 provides built-in support for voice and video as well as offering QoS transmissions (Emerging Technologies, 2004).
According to "Emerging Technologies," "HiperLAN2 also provides for unicast, multicast, and broadcast transmissions. Most experts see it as the most advanced wireless standard currently available" (emphasis added) (p. 6). Vance points out that North America continues to dominate global sales, though, accounting for 71% of the market, while the Asia/Pacific region represented 18% of the total, and Europe/Middle East/Africa (EMEA) and the rest of the world total 8% and 2% of the worldwide total respectively. According to this author, "There are two key factors responsible for the slower rate of adoption of 802.11b in Europe. First, until recently, Europe had its own WLAN standards -- HiperLAN and HiperLAN2 --which made it very difficult for 802.11b to gain any traction. Second, 802.11b operates in the 2.4 GHz spectrum, which is unlicensed in most of the world, with the notable exception of certain European countries. In Italy, for example, 2.4 GHz spectrum is regulated by the government and therefore is licensed" (p. 37). Nevertheless, the newer 802.11a standard, which operates in the 5-GHz spectrum, appears to solve some of these problems, while also providing customers with greater bandwidth (54 Mbps vs. 11 Mbps for 802.11b) and more non-overlapping channels (eight vs. three for 802.11b) (Vance, 2002).
HiperLAN2 and the 802.11 permutations remain the two primary protocols being used in the European and North American marketplaces; however, others are under development elsewhere around the world, a situation that in many ways echoes that being experienced in the cellular telephony industry. There, Europe (and most of the rest of the world except Japan) uses GSM ("Global System for Mobile Communications") while North America has adopted analog (AMPS -- "Advanced Mobile Phone Service") and digital (CDMA -- "Code Division Multiple Access"; TDMA -- "Time Division Multiple Access"). While GSM is available in the U.S. And Canada, coverage remains limited (Emerging Technologies, 2004).
Attention in GSM is being fueled in part based on growing interest in these global compatibility issues as well interest in a newly introduced add-on/successor to GSM called GPRS ("General Packet Radio Service"); this innovation provides always-on, higher-bandwidth data transmissions/Internet access. A comparable data enhancement to CDMA is called "1xRTT," and this technology started reaching the North American marketplace last year (Emerging Technologies, 2004).
The data transmission service of analog cellular in North America (CDPD -- "Cellular Digital Packet Data") provides Internet access and has been available for some time now; CDPD already provides wide coverage in the United States, but this technology continues to be constrained by a relatively slow transmission rate of 19.2 kbps (kilobits per second), a rate that is appropriate for e-mail, perhaps, but woefully inadequate for Web browsing applications (landline modems generally operate at 56 kbps). The CDPD service is available for both hand-helds and laptops through PC cards such as Novatel's Merlin series; some of the more high-end PC cards, such as Sierra Wireless' AirCard, employ compression software to further enhance access speed. Still another - and faster -- alternative introduced in the United States has been the Ricochet network; this system operates at 128 kbps; although the network's parent company, Metricom, declared bankruptcy in August, 2001, Aerie Networks purchased the Ricochet network and has announced plans to resume service in the United States (Emerging Technologies, 2004).
Much of the attention in the mobile phone domain for the past several years has been focused on 3G, the third-generation cellular network; this approach combines high-speed mobile access with Internet Protocol (IP)-based services thereby providing faster, more reliable, always-on connections (Emerging Technologies, 2004). According to Anderson, Bikson, Hundley and Neu (2003), "Third-generation (3G) wireless is the designation applied to multimedia (voice, data, and video) cellular phones and networks that will be deployed over the next few years. These 3G cellular phones have a much larger bandwidth than the…