Know your high-speed wireless LAN options

June 1, 2011
As they go from being networks of convenience to mission-critical systems, wireless LANs require careful planning and administration.

As they go from being networks of convenience to mission-critical systems, wireless LANs require careful planning and administration.

By Scott D. Thompson, Oberon Inc.

Six or seven years ago I used a Nokia E61i smart phone to connect to GSM (Global System for Mobile Communications) networks to receive email, and to have some Internet connectivity on the road. Although this was great at the time, connectivity was "spotty" and download speeds were quite slow in most locations. The phone was dual-mode so it offered the ability to connect to WiFi networks. This worked well in the office (once we figured out to permit it to authenticate to our network), but the public WiFi networks were not ubiquitous at the time, and could not always be counted on for availability.

The 2010 Cisco Visual Networking Index study projects cumulative average growth rate (CAGR) of 108 percent between 2009 and 2014 for global mobile data. This annual doubling in data is largely due to growing mobile video and Web usage, and the prevalence of laptops, tablets, pads and smartphones. The FCC has issued a report (Mobile Broadband: The Benefits of Additional Spectrum) that, based on demonstrated growth in data demands over the last few years, forecasts a shortfall in available cellular/personal communications service (PCS) spectrum to support this growth in 2012.

In all likelihood, more mobile data will be offloaded to available WiFi networks, or private wireless LANs. The latest Institute of Electrical and Electronics Engineers (IEEE; wireless networking standard, the 802.11n amendment, offers greater than 100-Mbit/sec TCP/IP (Transmission Control Protocol/Internet Protocol) throughput. The 802.11n products are mature and widely available, and, if the wireless and supporting cabling infrastructure is properly designed and deployed, offer satisfactory performance.

Is your network ready for the expected sharp rise in mobile-data traffic that will be generated by applications such as this, the Facetime feature available with Apple's iPad2? Photo courtesy of Apple

But can 802.11n products support doubling mobile data volumes year after year? Certainly there is a great deal of opportunity in the amount of spectrum available in the 5-GHz band in which 802.11n products may operate. There is almost 500 MHz of bandwidth available for use in the 5-GHz WiFi spectrum, which greatly exceeds the combined cellular and PCS spectrum, which is presently 170 MHz. Couple this with the fact that the WiFi network at 5 GHz can engage a great deal of spectrum re-use, meaning access points on the same channel can be used in fairly close proximity to one another due to the limited propagation capability at 5 GHz. As indicated earlier, if the WiFi network is properly designed, and the supporting cabling infrastructure is commensurate with the wireless capacity, IEEE 802.11n products can certainly provide a great deal of capability. But is there an emerging wireless standard to keep pace with the growth in mobile data demands?

802.11 evolves

Over the past decade the IEEE has come up with amendments to the original IEEE 802.11 wireless networking standard. The IEEE 802.11a amendment increased modulation rate and prescribed operation in the 5-GHz band. The 802.11g amendment increased modulation rate in the 2.4-GHz band. The 802.11n amendment increased channel bandwidth, modulation rate, and the number of antennas, operating in both the 2.4- and 5-GHz bands, to achieve unprecedented data rates.

The emerging IEEE 802.11 amendments are 802.11ac "Very High Throughput < 6 GHz" and 802.11ad "Very High Throughput at 60 GHz." 802.11ac takes advantage of the approximately 500 MHz of bandwidth in the 5-GHz band, advanced modulation techniques, and 4 to 8 antennas to achieve approximately 1 Gbit/sec over-the-air data rates and probably 400- to 500-Mbti/sec TCP/IP rates at the Ethernet connector. Because 802.11ac operates in the 5-GHz band, it is reasonable to assume that a site survey done for 802.11n at 5 GHz will be "correct" in coverage for 802.11ac at 5 GHz. The 802.11ac will just provide higher data rates.

IEEE 802.11ad takes advantage of a whopping 7 GHz of available spectrum at 60 GHz to provide for (anticipated) >1 Gbit/sec TCP/IP throughput at the Ethernet connector. Because 60 GHz is a millimeter-wave operation, the signal will not penetrate well through walls, and so it is best suited for "in-room" operating connecting stations to stations, or a station to a display.

Both amendments are on schedule for approval in December 2012 at this time, and of course, this may be delayed. Once approved, it could be several years before products are widely available. So 2015 is an early estimate as to when product may become available. In the cabling and infrastructure business, the design must anticipate technology demands 15 years down the road. So even if products designed to these new amendments slip 5 or even 10 years beyond 2015, the infrastructure designer must be anticipating them.

Questions to ask and answer

Regardless of the exact timeline, the infrastructure designer must consider the following.

  • Migration to 802.11ac will at least double the TCP/IP throughput of 802.11n
  • High-spectrum re-use to achieve high capacity will engage densely spaced, dual-band, wireless access points with video running across them.
  • Zone cabling may be considered to minimize the impact of horizontal cables on pathways and spaces, and to distribute edge switches.
  • Edge switches may need high-speed uplinks.
  • What is the impact of Power over Ethernet on the telecommunications room, in terms of heat and power?
  • What is the requirement for other wireless services, including in-building wireless, femtocells, building automation systems, real-time location systems, radio-frequency identification and others?
  • IEEE 802.11ad at 60 GHz will likely be restricted to "in-room" connectivity.

Inevitably the wireless LAN moves from being a network of convenience to a business/mission-critical network. In order to best utilize technology, some recommendations include moving PCs, laptops, tablets and other bandwidth-intensive devices to the 5-GHz band wherever possible, due to the greater available bandwidth. Smartphones are "dual mode" (cellular and WiFi), but most of them operate only in the 2.4-GHz band at this time. As IEEE 802.11ac emerges, anticipate that more laptops, tablets, pads and smartphones will be geared for operation in the 5-GHz band. To use the most spectrum possible, engage a multi-carrier in-building wireless or distributed antenna system.

Finally, think of the WiFi network as being truly mission-critical. Consider the following relative to the infrastructure.

  • How are access points secured environmentally?
  • Is RF coverage optimized at the mounting location?
  • Is the integrity of the site survey preserved?
  • Can access points be accidentally moved or disconnected from the network?
  • Are access points installed in compliance with codes, industry-specific physical security requirements, healthcare-specific requirements and others?
  • How do the access points look when installed? Is the installation consistent with the aesthetic or architectural requirements of the facility?

Emerging wireless standards, technology and the FCC making new spectrum available for wireless service certainly will improve wireless performance. But to keep up with doubling annual mobile data demands, the responsibility will largely fall on the shoulders of the wireless and cabling infrastructure design personnel to provide the optimum design for the facility.

Editor's note: This article is a companion to a presentation the author gave during a Web seminar entitled "In-Building Wireless Systems," which can be seen at

Scott D. Thompson is president of Oberon Inc. (

Government going mobile

In this article, Scott D. Thompson discusses the anticipated annual doubling of global mobile data for several years running. He points out that enterprise wireless local area networks must be equipped to handle such significant loads. Among the user types contributing to this enormous growth is the United States government. Members of its workforce are increasingly using mobile devices to carry out their everyday responsibilities.

Recently Cabling Installation & Maintenance interviewed Rich Tkac, vice president and executive director of American Systems' ( design and installation services division. American Systems provides systems engineering, technical and managed services to government customers. Tkac's division provides design and installation services for information technology including voice, data, security and wireless systems. As a professional who has observed, and met, the technology needs of government entities, Tkac offers here his perspective on their current and potential future mobile-use trends, as well as their existing wireless LAN strategies.

CI&M: Can you characterize a "typical" wireless LAN setup in a government office? Do they have ubiquitous access points throughout their facilities? Is wireless access limited to certain areas? Or does the approach vary from office-to-office or agency-to-agency?

Tkac: A typical wireless LAN setup in a non-intelligence government office provides employees and guests throughout the building general connectivity to the Internet and limited connectivity to the LAN. In a building in which the LAN may provide the potential for access to classified data, overall access to the LAN is limited to employees within specified sections of the building structure. Offices housing Department of Defense or intelligence-community personnel that prioritize the security of all data allow limited wireless access to all employees with the exception of certain physical areas or confines of the structure.

CI&M: Are government agencies embracing mobile devices for their workforce?

Tkac: There is no doubt that government is going mobile. Since 2008, federal agencies have increased efforts to support secure wireless communications for a mobile workforce. Mobile devices stand to fundamentally transform agency business processes, increase productivity and improve collaboration. Data security plays a key role as agencies explore mobile technology. Federal policies on wireless technology for the workforce are often determined on an agency-by-agency basis. The trend toward mobility is least popular among defense agencies and the intelligence community, which deal with top security issues.

CI&M: Are smartphones and tablets becoming more common among these agencies' workers?

Tkac: The explosion in popularity of smartphones and tablet devices within the commercial sector has piqued government interest. Federal IT departments often look to the private sector for best practices to integrate the latest technologies into existing government architectures.

One of the leading adopters of smartphones and tablet devices within government is the military (as recently reported by Computerworld magazine). The modern soldier needs a reliable, familiar device with complete operational capabilities. Because smartphones have usability comparable to a device that a solider uses at home, training time needed to educate warfighters on the latest communications devices is significantly reduced. Additionally, smartphones and tablet devices can be deployed in the battlefield more quickly than robust communications equipment that costs more than a smartphone or tablet device.

While federal IT departments see opportunities for adapting existing state-of-the-art applications in areas such as scanning, RFID, tagging and remote logging, there is still a concern for the potential of non-professional abuse of mobile devices equipped with these capabilities. Agencies must continue to research and further understand application restriction levels as well as develop a set of policies and standards prior to widespread mobile implementation across government.

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