Devices | Advantages of Wi-Fi

Wi-Fi was initially thought of as a data network only. Partially, this was because of an attempt to avoid the bad image that cordless phones also projected, as users were far too used to static and interference on cordless phones. But mostly, the original iterations of Wi-Fi occurred when Wi-Fi itself was struggling to find a place, and allowing users to check email or surf the Web while moving from room to room seemed to be enough of an application to motivate the fledgling industry.

But when mobile data networking took off, and people became addicted to remote email over the cellular network, the seeds were sown for device vendors to want to integrate Wi-Fi into their mobile devices. And because those devices are primarily phones, the connection of mobility to voice over Wi-Fi was natural.

Broadly, there are two categories of voice mobility devices that use Wi-Fi as a connection method. The first are Wi-Fi-only devices. These devices are often dedicated for a specific application in mind. For example, Vocera Communications makes a Wi-Fi-based communicator that is often used in hospitals to allow doctors and nurses to communicate with each other using voice recognition, rather than a keypad, to determine whom to call.

This device looks and acts more like a Star Trek communicator than a phone, but is an excellent example of voice mobility within a campus. Polycom, through its SpectraLink division, Cisco, and Ascom all make handsets that look more like a traditional mobile phone. In all of these cases, single-mode networking—using just Wi-Fi, in these examples, as the only means of connectivity—makes sense for the environment and the application.

The second type is made of mixed-mode, or integrated devices. These devices are mobile phones, made to be used with the cellular network as well as Wi-Fi. Nearly every mobile handset manufacturer is selling or is planning on selling such a device, including Research in Motion, Nokia, Samsung, and Apple with its iPhone. These devices can be made to place voice calls directly over the Wi-Fi network, rather than the cellular network, thus unlocking the entire fixed-mobile convergence (FMC) industry.

In both cases, the push from Wi-Fi networks originally designed for data allows for voice to become a leading, if not the dominating, purpose for many networks, as the maturity and variety of Wi-Fi-enabled voice devices make voice mobility over Wi-Fi possible.

Universal Presence | Advantages of Wi-Fi

Even though the focus—and of so many people—is with enterprise and large-scale deployments, in explaining what makes Wi-Fi compelling, we must not lose track of the consumer, and how consumer demands have pushed the entire Wi-Fi industry forward, inevitably benefiting the enterprise.

The major contribution the consumer space has given Wi-Fi is that is has driven people to demand wireless. Three historic events changed the landscape of mobility and connectivity: the Internet moved into the home; laptops replaced desktops and were being issued by corporate IT for usage everywhere; and darkly roasted coffee came onto the scene. Or rather, for the last one, people began to find reasons to want to work and live outside of the home and office. All three demanded a simpler solution than having to drag oversized telephone cables around with each user. And that gap was filled with Wi-Fi.

Wi-Fi is now in many places that mobile users are expected to show up in. In the home, it is difficult now to find a consumer-level gateway that does not include wireless. Just as television once was the centerpiece of the living room, but contention over control of the remote and the drop in prices lead televisions to spring up in nearly every room of the house, the Internet has migrated from being connected to one prized home computer in the living room to being spread throughout the house by Wi-Fi. In the enterprise, the advantages of unwiring the network edge has lead to IT organizations peppering the office with access points. And on the road, hotels, airports, cafes, and even sporting arenas have outfitted with Wi-Fi, to try to encourage their customers to get back with their online selves as often as possible, and maybe make each one be a little more "sticky" in the meanwhile.

What this means for voice mobility is that the cycle of demand drives the technology to get ever better. Consumers' demand and expectations "pull" advanced wireless into the home, just as enterprises "push" laptops onto their employees, encouraging them to be used outside the office, therefore increasing the number of hours employees think and do their work far beyond the amount of time each employee spends in the office.

And with this cycle of demand also comes maturity of the underlying technology. Wi-Fi has gone through a number of iterations, getting faster, more powerful, and less prone to mistakes. Now, it is nearly impossible to find laptops without wireless built in. It is even an option on many desktop systems, not considered to be traditionally mobile, yet eager to be joined in on the wireless bandwagon to help company's save on cabling costs.

Unlicensed Spectrum | Advantages of Wi-Fi

Generally, the ability to transmit radio signals over the air is tightly regulated. Government bodies, such as the U.S. Federal Communications Commission (FCC), determine what technologies can be used to transmit over the air and who is allowed to operate those technologies (see Figure 1). They do this latter part by issuing licenses, usually for money, to organizations interested in transmitting wirelessly. These licenses, which are often hard to obtain, are required in part to prevent multiple network operators from interfering with each other.

 

Figure 1: The United States Spectrum Allocation. Wi-Fi operates in the circled bands

The advantage of Wi-Fi, over other wireless technologies such as WiMAX (which we will cover in Chapter 7), is that no licenses are needed to set up and operate a Wi-Fi network. All that it takes to become a network operator is to buy the equipment and plug it in.

Clearly, the array of allocations within the spectrum is bewildering. And network operators for licensed wireless technologies must be aware of the rules for at least the part of the spectrum that their technology works in, to avoid violating the terms of the license. But, thankfully, all of this is taken care of automatically when 802.11 technology is used. Wi-Fi operates in two separate stretches (or "bands") of the radio spectrum, known in the United States as the Industrial, Scientific, and Medical (ISM) bands, and the Unlicensed National Information Infrastructure (U-NII) bands. These bands have a long history, and it is no coincidence that voice lead the way. Many people first became familiar with the concept of unlicensed radio transmissions when 900MHz cordless telephones were introduced. These phones require no licenses, but have a limited range and do only one thing—connect the call back to the one and only one base station. However, the power from using wireless to avoid having to snake cables throughout the house and allowing callers to walk from room to room revealed the real promise of wireless and mobility.

For enterprises, the benefits of the freedom from using unlicensed spectrum are clear. Removing the regulatory hurdles from wireless brings the requirements for setting up wireless networks down to the same level as for wireline networks. Expanding the network, or changing how it is configured, requires no permission from outside authorities (ignoring the physical requirements such as building codes necessary to pull cables). There is no concern that a regulatory agency might reject a Wi-Fi network because of too many neighboring allocations. Enterprises gain complete control of their air, to deploy it how they see fit.

Because being unlicensed gave the potential for every user to be her own network operator, wireless networking settled into the hands of the consumer, and that is where we will continue the story.

The Advantages of Wi-Fi

Until now, we've looked at why voice is interesting and what makes it work over a network, but we haven't yet examined the technologies that truly make voice mobile. The advantage of mobile voice, when working properly, is that the elements of the underlying network fade away, and user sees only a familiar phone, in a mobile package. Of course, this requires cutting the cord, allowing users to make or receive calls from anywhere. So that we can understand how and why an unwired network is able to make the elements of the network disappear to the user, so to speak, we need to dive deeper and understand what the unwired network is made of.

Wi-Fi, the wireless local area networking technology based on the work from the standards branch of the Institute of Electrical and Electronics Engineers, uses the IEEE 802.11 standard to allow portable mobile devices to connect to each other over the air, transmitting IP-based data as if they were connected directly with a cable.

But being wireless alone does not explain why Wi-Fi has become the primary wireless technology for both consumer- and enterprise-owned networks. Wi-Fi technology has a number of advantages that make it the obvious choice for wireless data, and for many circumstances, for mobile voice as well.

What is the Difference between Wi-Fi and IEEE 802.11?

Almost everywhere, the term Wi-Fi is now used to refer to the networking technology based on the IEEE 802.11 standard. There are subtle differences, however, between the two terms.

The term Wi-Fi is a trademark of the Wi-Fi Alliance, a nonprofit industry organization made up of nearly all of the equipment providers manufacturing IEEE 802.11 -based devices: chipset vendors, consumer and enterprise access point vendors, computer manufacturers, and so on. The Wi-Fi Alliance exists for two reasons: to promote the use of Wi-Fi certified technology throughout the industry and within the press, and to ensure that wireless devices based on 802.11 work together. The term Wi-Fi, and the accompanying logo, can be used only for products that have passed the Wi-Fi Alliance's certification programs.

We'll discuss the Wi-Fi Alliance more later, and where the Wi-Fi Alliance's certification programs diverge from the IEEE 802.11 standard. In the meantime, remember that 802.11 and Wi-Fi mean almost the same thing.

Example of the Wi-Fi Alliance Certification Logo.

Note

the logo is the trademark of the Wi-Fi Alliance and is shown here for example purposes only.