One of the most promising technologies to hit the multihousing and commercial properties market is that of the wireless local area network (WLAN). The concept of a technology that will distribute broadband network connectivity to tenants or residents regardless of the properties wiring situation while offering the added perk of mobility is an attractive amenity for almost any property.

However, while the WLAN market has been growing at a steady pace, it has not swept the MDU/MTU industry like wildfire. Property owners and developers have been cautious in their embrace of the technology. "At the 2001 Multihousing.com Technology Conference (www.multihousing.com) a number of leading property owners stated that they were all very much encouraged by wireless technology but that as a group they felt it was not quite ready for prime time as of yet," said Larry Kessler, President & CEO of InteliCable and Multihousing.com.

Now, a year removed from that event has WLAN technology progressed to a greater level of acceptance among owners and developers? "As we gear up for the 2002 event (April 8-9), I expect WLANs to be one of the hot topics," said Kessler.

Fueled by the growth of mobile computing devices, such as laptops and personal digital assistants as well as the ability to overcome critical wiring issues, WLANs are rapidly expanding their role in the MDU/MTU market.

How WLANs generally operate
According to wireless network integrator CDCE (www.cdce.com) a WLAN is an Ethernet network based upon the IEEE's 802.11b standard. Users connect to local area networks (LANs) through radio connections typically in the 2.4 GHz band. WLANs can be integrated transparently into any LAN environment, and are compatible with all major network operating systems.

Any Ethernet-equipped workstation can be connected wirelessly, including PCs, Macintosh, machine tools, and servers. Depending upon which products are used to construct it, a WLAN can connect X-Terminals, UNIX hosts, SUN, HP, DEC, IBM and other workstations.

In a WLAN, wireless network interface cards (NIC) are inserted into notebooks to replace conventional wired NICs. Wireless station adapters replace conventional wired desktop LAN connections. Access points and antennas are positioned throughout the area to be covered based upon a site survey performed by your wireless integrator.

WLANs offer users all of the functionality of Ethernet, while permitting them to roam about your properties premises connected to your LAN. Users are able to connect to such applications as Outlook or Exchange, and to proprietary applications, just as they would at their desktops, from anywhere within a given range.

The extent of this range varies with the nature of the wireless network. Range is one of a number of variables that are determined during the network design process.

Wireless technologies for LAN connection include frequency hopping, direct sequence, microwave, and infrared transmission light. To date, the most practical of these for enterprise purposes have proven to frequency hopping and direct sequence.

Depending upon the type of spread spectrum technology employed, WLAN delivers between 1 and 3 Mbps, or up to 11 Mbps. The decision as to which spread spectrum technology to deploy, and how to deploy it within a given environment, involves a host of variables that should be determined in collaboration with your wireless integrator, and preferably also with an RF engineering team.

Understanding 802.11
When discussing WLANs, the terms 802.11 or 802.11b are often referenced. What these refer to are different types of engineering standards associated to the technology.

"The IEEE (Institute of Electrical and Electronic Engineers) is a professional society that serves the electrical engineering community through publications, conferences and standards development activities," Bob Cifelli, CTO of QN Global Solutions (www.qnglobal.com). "802 is the IEEE committee responsible for setting standards defining Media Access Control (MAC) and Physical (PHY) layer communications in Local Area and Metropolitan Area Networks (LAN/MAN). Underneath 802 are several families or subsections that define various types of network topologies. For example 802.3 describes Ethernet, 802.5 describes Token Ring and the 802.11 committee describes wireless LANs.

"The 802.11 standard defines some aspects of frequency hopping (FHSS) and direct sequence spread spectrum (DSSS) radio systems for use in the 2.4 MHz ISM (Industrial, Scientific, Medical) band. FHSS and DSSS are basically two different approaches to dealing with RF signal interference and co-existence of multiple systems. In 802.11, the DSSS PHY specifies a maximum data rate of 2Mbps with a fallback data rate of 1Mbps for very noisy environments. The standard defines the FHSS PHY to operate at 1Mbps and allows for 2Mbps operation in very clean environments.
· 802.11b: commonly referred to as 802.11 High Rate, 802.11b is a supplement to the IEEE standard for DSSS wireless LANs. Most 802.11b products have data rates of up to 11 Mbps, even though the standard does not specify the techniques for achieving these data rates. This standard can be thought of as the definition of the migration from 2 Mbps DSSS to 11Mbps DSSS. This is similar to the migration from 10Mbps Ethernet to 100Mbps Ethernet. FHSS systems remain unchanged.
· 802.11a: A revision to the IEEE standard that operates in the unlicensed 5 GHz band. Most 802.11a products have data rates up to 54 Mbps.

"Please remember, these speeds are theoretical and will vary depending on how many users are active and how clean the RF environment is in the operating area."

Note: For further study on the IEEE 802 family of protocols and standards see http://standards.ieee.org/catalog/olis/lanman.html.

Looking at WLAN Market Expectations

Cahner's In-Stat Group (http://www.instat.com) recently released its 2002 WLAN market report and announced that "Although the economy remains troubled, and business budgets remain tight, unit shipments in both the home and business will grow throughout the next three quarters, albeit at a slower pace than in 2000 and the first half of 2001," says Gemma Paulo, an industry analyst with In-Stat. "Falling prices for both 802.11b clients and infrastructure will contribute to this unit growth, although will have a negative effect on expected revenue growth."

In a separate report in January of this year, Infotech (www.thephillipsgroup.net) projected WLAN end-user revenues to reach $4.4billion by 2005. "The key drivers for WLAN growth are declining product prices, increased laptop deployment, the appearance of devices with embedded wireless LAN capabilities, the availability of higher-speed products, the push for increased employee productivity, and the expanded reliance upon the Internet," stated InfoTech's senior analyst, Shelly Tyler Radler.

The Security Issue
The concept of broadcasting sensitive company data through the air, especially when competitive businesses occupy the same property, is one of the major concerns when considering the implementation of a WLAN. Are WLANs secure enough today to provide tenants with the comfort level they need?

According to the Wireless LAN Association (WLANA; www.wlana.org), a non-profit educational trade association comprised of the thought leaders and technology innovators in the local area wireless technology industry, data security considerations that impact the entire network architecture also apply equally to wireless LANs. But the very different physical layer of wireless LANs actually increases overall network security due to the following facts:

Spread Spectrum Technology
Most wireless LANs use spread-spectrum radio transmission techniques. Spread spectrum technology was first introduced about 50 years ago by the military with the objective of improving both message integrity and security. Spread-spectrum systems are designed to be resistant to noise, interference, jamming, and unauthorized detection. Spread spectrum transmitters send their signals out over a broad range of frequencies at very low power, in contrast to narrowband radios that concentrate all of their power into a single frequency. There are several ways to implement spread spectrum transmission, the two most common being direct sequence (DS) and frequency hopping (FH).

Both techniques present unintended receivers with a difficult problem. In the case of DS, an eavesdropper must know the chipping (spreading) code. Someone trying to intercept an FH transmission must know the hopping pattern, In both cases, the specific frequency band (or portion thereof, in the case of DS) and modulation techniques in use must also be known. Radio systems also use a form of data scrambling for purely technical reasons, which is to assist in managing the timing and decoding of radio signals. An unintended receiver would also need to know this scrambling pattern.

Infrared-based wireless LANs are often used in high-security applications because infrared signals do not penetrate solid objects, like walls. Thus a project team could be literally cut off from the outside world and still have the benefits of a LAN. Some products use narrowband radio, which does not use spread-spectrum transmission. While this technique certainly works, it is not as inherently secure as spread-spectrum, and encryption is therefore a must when this technology is used.

But all of these techniques allow the use of encryption, and indeed, many wireless LAN products include encryption features as a standard or optional component. The IEEE 802.11 standard, for example, includes a security technique known as "wired equivalent privacy" (WEP), which is based on the use of 64-bit keys and the popular RC4 encryption algorithm. Users without knowledge of the current key (password) will find themselves excluded from network traffic. Encryption, as noted above, is always advisable on any network, and is certainly easier to implement in wireless LANs than in their wired counterparts.

Station Authentication
Most wireless LAN products have the ability, as an authentication management function, to specifically authorize or exclude individual wireless stations. Thus an individual wireless user can be included in a network, or, at any time, locked out. Users may also need to know a wide variety of information, including radio domains, channels (specific frequencies or hopping patterns), subchannels, security IDs, and passwords. Other configuration information relating to in-building roaming might also need to be known. Thus network administrators can make unauthorized network access very, very difficult even for hackers who possess the specific wireless equipment being used at a given site.

Physical Security
Surprisingly, eliminating significant amounts of wire from a given installation dramatically reduces the number of places for wiretappers to gain access to the wired physical plant. While wireless LANs usually involve the use of a wired backbone network for access-point interconnection, the amount of wire is quite small, and extra steps can be taken to safeguard its physical integrity without inordinate cost. Moreover, since the access points used in wireless LANs function as bridges, individual wireless users are isolated from perhaps the majority of LAN traffic, again limiting user access to raw network packets.

WLANA also points out that the diligent management of security is essential to the operation of local-area networks, regardless of whether they have wireless segments or not. It¹s important to point out here that absolute security is an abstract, theoretical concept - it does not exist anywhere. All LANs are vulnerable to insider curiosity, outsider attack, and eavesdropping. No one wants to risk having the LAN data exposed to the casual observer or open to malicious mischief. Regardless of whether the network is wired or wireless, steps can and should always be taken to preserve network security and integrity.

Today and Tomorrow

The continued growth in the marketplace combined with reduced equipment costs, better technology, security measures and the overall greater level of familiarity and acceptance by the general public with wireless devices points to a burgeoning technology that is going play an increasingly significant role in the lives of property owners and developers.

Being able to offering mobile connectivity to tenants and ability to wirelessly retrofit properties are both attractive market drivers but they do not come with our tradeoffs. As Steve Stroh points out in his, "Unintended Consequences of High-Efficiency Lighting" article (page XX), and Gerry Lederer as well in his "2002 Telecom Checklist" (page XX) the advent of on-premise wireless solutions also creates a host of new concerns that owners and developers need to understand today. Interference issues will become a real concern as more and more wireless technologies are adopted by tenants but how much of a concern they become is dependent on the work owners and developers do today to educated themselves with the technology and plan accordingly for tomorrow.

SIDEBAR: Select List of WLAN Manufacturers

Agere Systems: www.agere.com
Buffalo Technologies: www.buffalotech.com
Cisco Systems: www.cisco.com
Colubris Networks: www.colubris.com
Enterasys: www.enterasys.com
Intermec: www.intermec.com
Intersil: www.intersil.com
Linksys: www.linksys.com
Proxim: www.proxim.com
Raylink: www.raylink.com
Symbol: www.symbol.com