Wireless Technology Industry Report (2005-06)
- The forecast where technology will be on the future of wireless LAN
- The current level of wireless technology
- The development of wireless networking
- The influence on the future of wireless LAN
- The trend of the time of wireless networking
In June, 1997 the IEEE, the body that defined the dominant 802.3 Ethernet standard, released the 802.11 standard for wireless local area networking. IEEE 802.11 standard supports transmission in infrared light and two types of radio transmission within the unlicensed 2.4GHz frequency band: Frequency Hopping Spread Spectrum (FHSS) and Direct Sequence Spread Spectrum (DSSS).
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The followings are the development of wireless standards:
Local Area Networks (IEEE 802)
Wired Ethernet (IEEE 802.3)
Wireless Ethernet (IEEE 802.11)
High Rate Wireless Ethernet (IEEE 802.11b)
Mode 2.4 GHz/54 Mbps Wireless Ethernet (IEEE 802.11g)
5 GHz Wireless LAN/WAN (IEEE 802.11a)
Wireless Personal Area Network (IEEE 802.15)
Fixed Broadband Wireless Access (IEEE 802.16)
European 5 GHz/54 Mbps WAN (HiperLAN2)
Short Distance Device Interconnectivity (Bluetooth);
HomeRF Wireless LAN
Wide Band Frequency Hopping (WBFH)
The most sparkling stars of wireless networking technology today is IEEE 802.11b.The 802.11b wireless networking has enjoyed a rapid increase in adoption in enterprise settings and in educational and institutional networks. More recently, particularly in the past year as adapter and access point prices have lowered dramatically, 802.11b wireless network products have been making inroads into home and SOHO applications.
Initially, the demand for 802.11b in the home was driven by people who used a wireless-equipped notebook computer at work, and then took it home and wanted the same freedom from wired connection there too. As prices for wireless components came down, and as home networking to share broadband Internet connections increased, 802.11b was and still is the go-to choice, even in households to which no one comes home with a wireless-enabled notebook from work.
Development of wireless technology
The interference and performance issues at 2.4-GHz have the wireless LAN industry headed for the open 5-GHz frequency band, where the opportunity exists for a much cleaner wireless networking environment. Similar to the 2.4-GHz band, the 5-GHz spectrum does not require a license for use throughout much of the world. In addition, 5-GHz is void of interference from microwaves and has more than twice the available bandwidth of 2.4-GHz, thereby allowing for higher data throughput and multimedia application support.
The open 5-GHz spectrum offers an opportunity for the industry to create a unified wireless network for a broad range of devices and applications. IEEE 802.11a and ETSI (European Telecommunications Standards Institute) HiperLAN2 wireless LAN standards. This 5-UP (5-GHz Unified Protocol) proposal supports interoperability with the existing standards while providing for increased scalability both up and down. Whereas the IEEE 802.11a and ETSI HiperLAN2 wireless standards support 6 to 54Mbps, 5-UP allows devices to operate from 128Kbps to 108Mbps in 128Kbps increments.
With 5-UP enhancements, a wide range of devices-stretching from low to high data rates-can all communicate on a single wireless network. Everything from cordless phones to high-definition televisions and personal computers can communicate on the same multipurpose network under a single unified protocol.
Intel Corporation integrated, “wireless-Internet-on-a-chip” technology could enable a new era of wireless Internet-access products with extensive battery life and greater processing power. The new research chips feature logic (microprocessor), flash memory and analog communications circuits on a single piece of silicon built using a single manufacturing process. Each of these types of circuits is traditionally manufactured on separate process technologies in different factories. Chips produced on the new process may be up to five times more powerful than those used in today.
Could mundane wireless local area networks (WLANs) eat into the profit potential of flashier third-generation (3G) mobile carriers? A flurry of reports this week seems to indicate that this is entirely possible. The growth of public WLAN “hotspots” in airports, hotels, libraries – even coffee shops – portends revenue from wireless LANs skyrocketing to $868 million by 2006. In 2000, money from WLANs raked in just over $1 million.
Fueling the increased interest in WLANs is the relative and growing ease of availability of fast Internet access for handhelds and the increasingly common use of wireless networks in the home and office, say analysts.
The ease of installing and using WLANs is making it an attractive alternative to mobile 3G. In contrast to the reported $650 billion spent worldwide by carriers to get ready for 3G, setting up a WLAN hotspot requires only an inexpensive base station, a broadband connection, and one of many interface cards using the 802.11b networking standard now available for your laptop, PDA, or smartphone.
Will WLANs supplant 3G? No, aside from the fact that the two technologies use different radio frequencies, they are also targeting different markets. Where 3G is mostly phone-based and handles both voice and data, WLAN is a purely data-driven creation.
The high bandwidth of wireless networking environment and more powerful chips will integrate the new era of wireless networking. Then, wireless networking will be more convenient. Today, the WLAN has redefined what it means to be connected. It has stretched the boundaries of the local area network.
It makes an infrastructure as dynamic as it needs to be. In the future wireless world, the freedom to access real-time information anywhere, anytime not within a building or multi-building complex anymore. Wireless networking can be configured to meet the needs of a specific application, from enterprise environments to small businesses or even home applications.
J. Walker, “Unsafe at any key size: an analysis of the
WEP encapsulation,” Tech. Rep. 03628E, IEEE 802.11 committee,
March 2000. http://grouper.ieee.org/groups/802/11/Documents/
N. Borisov, I. Goldberg, and D. Wagner, “Intercepting Mobile Communications:
The Insecurity of 802.11.” http://www.isaac.cs.berkeley.
L. Blunk and J. Vollbrecht, “PPP Extensible Authentication Protocol
(EAP),” Tech. Rep. RFC2284, Internet Engineering Task Force (IETF),
Lucent Orinoco, User’s Guide for the ORiNOCO Manager’s Suite,
J. Walker, “Overview of 802.11 security.” http://grouper.ieee.org/groups/802/15/pub/2001/Mar01/01154r0P802-15_TG3%-Overview-of-802-11-Security.ppt, March 2001.IEEE 802.11Working Group. http://grouper.ieee.org/groups/802/11/index.html.
Since 1989, the wireless industry began to explore by adapting digital
technology replacing the existing analog network as a means of improving capacity due to the increase of wireless service demands. Digital has a number of advantages over analog transmission:
• Economizes on bandwidth
• Allows easy integration with personal communication systems (PCS) devices
• Maintains superior quality of voice transmission over long distances
• Difficult to decode
• Can use lower average transmitter power
• Enables smaller and less expensive individual receivers and transmitters
• Offer voice privacy
At that period, Time Division Multiple Access (TDMA) was chosen to replace Motorola’s Frequency Division Multiple Access (FDMA) technology which known today as narrowband analog mobile phone service. FDMA allocates a single channel to one user at a time. FDMA is wasteful of bandwidth: the channel is assigned to a single conversation whether or not somebody is speaking. Moreover, it cannot handle alternate forms of data, only voice transmissions. Qualcomm then introduced the Code Division Multiple Access (CDMA) technology to compete against TDMA technology to provide digital service. Now the two major competing systems (TDMA and CDMA), have been a topic for debate throughout the wireless community over which technology has the superior quality.
WHAT IS TDMA?
TDMA is digital transmission technology that allows a number of users to access a single radio-frequency (RF) channel without interference by allocating unique time slots to each user with thin a channel. The digital conversations from a single transmitter occupy different time slots in several bands at the same time
In TDMA, the access technique used exercises, three users, sharing a 30-kHz carrier frequency. TDMA is also the technology used in Europe where Global System for Mobile Communications (GSM) is the digital standard used to provide wireless access and in Japan where Personal Digital Cellular (PDC) is used as the standard. TDMA was chosen for these standards due to the reason that it enables some essential features for system operation in an advanced cellular or PCS environment. A single channel can carry all four conversations if each conversation is divided in short fragments, is assigned a time slot, and is transmitted in corresponding time bursts.
TDMA also offers the ability to carry data rates of 64kbps to 120 Mbps. This enables service providers to offer short message services as well as bandwidth-intensive applications such as multimedia and videoconferencing. Unlike other spread spectrum technologies, TDMA ensures the avoidance of interference from other users transmitting at the same time on the same frequency since users it separates the users in time. Also, TDMA installations offer substantial savings in base-station equipment, space, and maintenance, an important factor as cell sizes grow ever smaller.
One of the disadvantages of TDMA is that each user has a predefined time slot. Users roaming from one cell to another are not allotted a time slot. Therefore, if the user moves to another time slot, and all slots are occupied, the conversation may be disconnected. Another problem with TDMA is that it is prone to multipath distortion. A signal from a base-station to the mobile phone can take many directions. Thus, the signal can bounce of several buildings which can cause interference.
WHAT IS CDMA?
CDMA stands for Code Division Multiple Access. This means that the signal is coded, not only providing better security but also allowing multiple, simultaneous users. In other words, a large number of users share a common pool of radio channels and any user can gain access to any channel (each user is not always assigned to the same channel).
With CDMA, unique digital codes, rather than separate RF frequencies or channels are used to differentiate subscribers within on frequency. The codes are shared by both the mobile phone and the base station. The codes are called “pseudo-random code sequences”. CDMA uses a radio spectrum that is 1.25 MHz wide.
Increased privacy is a common trait of CDMA technology. CDMA calls will be secure from eavesdroppers. Unlike analog conversation, a simple radio receiver will not be able to pick up individual digital conversations out of the overall RF frequency band.
CDMA also provides “soft handoff”. In a cellular system, a user’s call switches from one cell site to another as the user travels. With CDMA, users are on the same frequency for the whole network, thus the mobile phone must only negotiate the “pseudo-random code” instead of switching to a whole new frequency which is known as a “hard handoff”. Therefore, the “soft handoff” offers transparent cell site switching, instead of having distorted audio due to “hard handoffs”.
A problem with CDMA is channel pollution. This occurs when signals from too many base stations are present and non are more dominant than the others. This then causes rapid degradation of audio quality.
The principle problem facing the wireless communication community is how to allow a large number of users access allotment of frequencies. In today’s wireless communication systems, there are two principle methods being used to multiplex users on the same frequencies, one by time, and the other by code. CDMA no doubt has the highest “spectral efficiency” of all the digital wireless technology. It can accommodate more users per MHz of bandwidth than any other technology. CDMA supporters claim bandwidth efficiency of up to 13 times that of TDMA and between 20 to 40 times that of analog transmission. CDMA has other benefits over other systems such as:
- Better signal quality
- Privacy of coded digital communications
- Soft handoffs when changing cell sites
- Easy addition of more users
It is quite obvious that CDMA technology is the wave of the future. But the main concern is the ability of the carriers to implement the system. TDMA systems have been operable for quite some time. Thus the network is by now well established. Fast “time to market” is essential to carriers due to the phenomenal pace of today’s wireless communications market, and many providers choose to incest in TDMA systems that have already been developed and proven.
Furthermore, the cost of installing new CDMA stations is much more expensive. A CDMA station would cost $300,000 in comparison to $80,000 per TDMA base station.
Other implementation complication includes backward compatibility. Consumers must possess dual mode phones in order to be compatible with other systems. But as CDMA coverage grows slowly, this will not be a problem.
With present developments, it is apparent that CDMA will eventually displace TDMA as the primary wireless technology. Since TDMA is a proven technology, it will be a viable alternative for markets that require lower capacity demands. Because CDMA is ideally suited for the high traffic demand of populated urban areas, CDMA systems will dominate these markets.
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