Naresh Kumar, General Manager, Application Engineering Organisation, Agilent Technologies India Private Limited

The world we live in today is much different from what it was even just a few short years ago. Increasingly it is being defined by any time, any place connectivity. Digital entertainment and communication is everywhere and available to billions of people personally, worldwide. Neighborhoods comprise wireless networks and even the most obscure songs and books are purchased at least once a quarter on the Internet. For instance, nearly 2 billion people use mobile phones on a daily basis ?? not just for their voice services, but for a growing number of social and mobile, data-centric Internet applications. Thanks to the mobile phone and service telecommunications industry revolution, average consumers today not only expect pervasive, ubiquitous mobility, they are demanding it.

A decade ago such mobile connectivity would have seemed inconceivable. After all, who would have imagined that one day the mobile phone would compete with the traditional landline for voice service?
Consider also the idea of onboard vehicle navigation or GPS. Years ago, most consumers would have been content using a map to navigate through unfamiliar territory, never even considering that an alternative might exist. These days though, vehicles with built-in navigation functionality and after-market GPS devices are waking consumers up to the true benefits of such a capability and the freedom of mobility that it allows.

Today, this type of mobile connectivity comes easily thanks to a wide array of mobile devices incorporating a range of new and emerging wireless standards and technology. One technology hoping to further cement this trend towards mobility on a global basis is Worldwide Interoperability for Microwave Access, otherwise known as WiMAX.

Although a relative newcomer to the commercial arena, WiMAX has garnered increasing attention from both consumers and technologists alike. Its popularity has been driven by its promise to quickly and cost effectively deliver super-fast broadband wireless access to underserved areas around the world, as well as recent developments in worldwide spectrum allocation and standardization. Also bolstering its popularity is the global support it has received in Europe, South Korea and the US.

While there is little denying the business opportunities and benefits that WiMAX promises to deliver, realizing its full potential will require innovation in terms of product development and commercialization. Just as critically, innovation will be required in the test and measurement solutions which will enable WiMAX to be realized in the real world.

What is WiMAX?
WiMAX is a wireless digital communication technology, based on the IEEE 802.16 and ETSI HiperMAN wireless metropolitan area network (MAN) standards. It can provide broadband wireless access up to 50 km for fixed stations (for example, desktop PCs), and 5-15 km for mobile stations (for example, notebooks, computers, mobile phones, personal media players, and PDAs). In contrast, the popular Wi-Fi is limited in most cases to only 30-100 metres. Like Wi-Fi and Bluetooth, WiMAX uses radio frequency waves as opposed to conventional wires to transmit the Internet and data to both fixed and mobile devices.

With WiMAX, Wi-Fi-like data rates are easily supported, but the interference issues that often affect Wi-Fi are lessened. Additionally, WiMAX allows more efficient bandwidth use and is intended to allow higher data rates over longer distances. Because it operates on both licensed and non-licensed frequencies, WiMAX provides a regulated environment and a viable economic model for wireless carriers.

The technology can be used for a variety of fixed (IEEE 802.16d-2004) applications including a “last mile” broadband connection, hotspot and cellular backhaul, and high speed enterprise connectivity for businesses. While some believe that fixed WiMAX is destined to become as widely used as digital subscriber line (DSL) and cable modem Internet access technologies, others feel that its true potential lies in its mobility. Mobile WiMAX (IEEE 802.16e2005) delivers another choice to existing cellular operators who could use it to supplement their networks in metropolitan areas with full-featured multimedia mobile applications including audio, data and video. New operators might deploy the technology to compete with the cellular networks. For the consumer, having mobile WiMAX capability essentially means that they can communicate wirelessly while riding in a car or walking down the street.

Regardless of its intended end-application, WiMAX features a number of unique benefits which make it a compelling sell these days in markets worldwide. To begin with, broadband wireless access is cheaper and easier to deploy. WiMAX offers lots of ratcheting in bandwidth for discrete services. Also, fewer base stations are required to create a network.

Another key benefit, being eyed by business strategists everywhere, is WiMAX’s capacity to deliver sufficient bandwidth to enable the “holy grail” in mobile communications ?? triple-play applications (for example, voice, video and data), including high speed data, toll-quality voice and multimedia content (see Fig). By offering triple-play services, carriers would be able to capture incremental revenues from the broadband access infrastructure.

Of course, delivering on this triple play while keeping costs low, requires that WiMAX providers bundle their wireless broadband services with voice over internet protocol (VoIP) capabilities. Doing so would allow consumers to reap the reward of a lower monthly bill, despite the initial investment involved in upgrading from dial-up Internet access to broadband. Also, it would add to the quality of their overall mobile experience. Today Wi-Fi hotspots allow mobile consumers to check e-mail or surf the web while drinking a morning cup of coffee. But walk out of the door and that connection is lost. If implemented successfully, WiMAX-enabled wireless VoIP could one day make that a thing of the past.

Integration with VoIP makes sense for WiMAX. If the technology only supports data, there is little compelling reason to justify build-outs. Voice provides the impetus to make providers more interested in the technology and to compel consumers to give it a try. Add the element of mobility to the WiMAX-VoIP combination and there is an even more compelling sell. After all, wireless VoIP networks are less expensive to set up and install than wired ones. They are also considered more secure in the face of natural disasters such as a hurricane where the “last-mile” of wired solutions may be physically damaged or destroyed.

Implementing WiMAX
How exactly will this vision of WiMAX come to fruition? The answer to that question lies in understanding the technology’s various stages of implementation: fixed, nomadic, portable, simple mobility and full mobility.

Fixed deployments are defined as stationary access to a single base station. An example of this type of deployment would be video conferencing for a convention center. Here DVD-quality video could be wirelessly broadcast to monitors in a convention center. With a sufficiently powered processing system these monitors could be started, restarted and stopped independently without affecting the quality of the video signal. Fixed deployments could also be used for wireless broadband backhaul that connects multiple Wi-Fi networks in a mesh network, replacing the optical lines currently used for this purpose.

Nomadic deployments are defined as stationary, but movable, access to a single base station. This deployment is similar to the cyber café concept where the user can connect from anywhere within the range of a base station. With this deployment, simultaneous support for hundreds of businesses with T-1 speed connectivity or thousands of residences with DSL speed connectivity would be possible.

Applications that are portable or mobile (for example, the device is in motion while a signal is being received and transmitted) are based on the IEEE 802.16e-2005 standard. Such mobile WiMAX systems have the ability to handoff a signal from one base station to the next, thereby creating “metro zones” which seamlessly provide continuous portable outdoor broadband wireless access in large cities and metropolitan areas and allow end-users to remain connected during their travels.

To date, products for both fixed and nomadic WiMAX applications have been commercially deployed. With the recent completion of the mobile version of the WiMAX (IEEE 802.16e-2005), products for portable applications have now begun making their way to market. While not yet available, WiMAX will eventually provide mobile wireless broadband connectivity without the need for direct line-of-sight to a base station.

The competitive view
While the WiMAX story seems quite compelling, it is not without its detractors. Critics argue that the grand vision of WiMAX is little more than hype and marketing dollars. They cautiously point to the fact that phones and laptop cards combining well-tested technologies like Wi-Fi and cellular might well prove to be cheaper and more reliable in the short term; although large-scale deployments will be necessary to prove the validity of that claim.

Even traditional cellphone companies seem reticent to adopt WiMAX, having already invested a fortune in building their own wireless voice and data networks and still hurting from having to write off exorbitant 3G costs. Instead they hope to recoup some of this investment through enhancements to the 3G mobile phone technology known as Universal Mobile Telecommunications System (UMTS). These enhancements will come in the form of the new 3G Long-Term Evolution (LTE) standard from the 3rd Generation Partnership Project (3GPP) and are expected to ensure that UMTS remains a highly competitive technology through 2010 and beyond.

By adopting many of the same techniques as alternative wireless technologies such as WiMAX, 3G LTE aims to evolve 3G toward a high-data-rate, low-latency and packet-optimized radio-access technology. It would also feature spectral flexibility to work in variable bandwidths, the ability to work in both unpaired and paired spectrum, support for very high speed mobility, and an IP-based core network. While its performance in a real network implementation remains to be seen as no commercial deployments yet exist, such features ?? if realized ?? have the potential to enhance 3G networks and enable some significant new service opportunities in relation to mobile TV and video.

WiMAX in India
All leading telecom operators in India are planning WiMAX implementation, and most cellular operators are already running trials in different cities in India. The spectrum allocation by the government is expected to happen before the end of this year. Given the pressure on pricing for the various voice and data services in India, WiMAX seems to provide a very economical long distance calling option. Also, given the investments made in GSM networks, WiMAX is most likely to coexist along with these networks in India.

Besides trials, there is a lot more happening on WiMAX in India. In WiMAX R&D, most of the chipset vendors are working on reference design validation. There is equal focus in the area of protocol stack development by software development teams.

Apart from this, hardware validation activity is also picking up speed in India. There are many companies which are investing in conformance labs for radio, protocol and interoperability.

With the immense potential of WiMAX, it won’t be long before this triggers manufacturing of customer premise equipment (CPE) for WiMAX in India.

Challenging times ahead
While the widespread global deployment of WiMAX creates significant business opportunities in terms of application, device, network and service innovation, it also leads to some compelling new challenges for the device manufacturer, service provider and network operator.

In the case of the device manufacturer, many of these challenges stem from the fact that the IEEE 802.16 standard leaves the decision regarding how a device such as a WiMAX handset is built up to the implementer. Standards-compliant devices therefore can vary widely from one company to another. As a result, the ability to take advantage of emerging market opportunities is closely tied to the manufacturers’ ability to test products for regulatory and standards compliance. It is also tied to the manufacturers’ ability to keep pace with emerging WiMAX applications in light of shrinking design cycles and timeto-market schedules. Regular WiMAX Forum-sponsored Plugfests also help ensure interoperability, but there is more work to be done. Another challenge is how to decrease a product’s design, manufacturing and test cost, while increasing its performance, functionality and quality.

Service providers and network operators face their own challenges when it comes to deploying WiMAX. They must ensure that the network and services offered are free from problems at the base station and on the network. This is especially crucial as capturing market share in this growing segment of the industry and reducing churn requires that the network be tested to guarantee optimal performance and quality. Consumers, who have come to demand ever more feature-rich products, with smaller form factors and smaller price tags coupled with quality of service (QoS), would expect nothing less.

The bottomline here is obvious: WiMAX is a challenge to build, deploy and maintain, given that there are any number of points of failure throughout its life cycle. The mobile device has to work properly. It must be able to seamlessly receive and transmit data from the base station and vice versa. The network must be able to handle this activity, as well as that of other subscribers, without resulting in dropped calls or slow data throughput. Quality therefore cannot be an afterthought. Rather, it needs to be built into all areas of the life cycle. Doing so is the only way to ensure that the device, network, etc. all work as expected.

The role of measurement
How well a company deals with these challenges will ultimately determine its success or failure in the burgeoning WiMAX market. It will also dictate the success or failure of WiMAX in the marketplace. That is exactly where measurement comes in. It can play a critical role in easing this burden by providing the assurance, quality and data sources companies require for technology development and commercialization.

Many people fail to realize that measurement is a derivative industry, meaning that it enables emerging industries like WiMAX and supports technology commercialization within that industry. Therefore, measurement solutions need to be developed alongside new technology development and commercialization.

When utilized appropriately, these solutions can offer significant benefits. They help proliferate standards like WiMAX by ensuring that devices, networks and services comply with any and all certification, conformance and regulatory requirements. They provide research and development engineers and manufacturers, as well as wireless communication service providers with the tools they need to successfully test their products, speed timeto-market and maximize return-on-investment. Measurement solutions also ensure that consumers using WiMAX are protected against substandard quality either in the device, network or service. As a result, measurement is a key enabler for accelerating the delivery of next-generation wireless communication based on WiMAX.

But what does that really mean in layman terms? It boils down to one simple fact. Measurement solutions do not make devices or build networks that transmit and receive WiMAX signals. Instead they ensure those devices and networks work as they are supposed to ?? with optimal performance and quality ?? so that when consumers open their mobile devices, for example, they can send data or connect to the Internet without the slightest problem. Measurement solutions do this by helping engineers test for any potential problems in the handset, the network, or at the base station, and by testing to ensure that products comply with standards and various government regulations. In doing so, they help ensure consumers get the high quality, performance rich, functionality packed WiMAX experience they paid for.

Conclusion
Realizing the true global potential of WiMAX and the business opportunities it foretells will require innovation in the development and commercialization of WiMAX. Just as critically, it will require innovation in the test and measurement solutions which will enable that technology to be realized in the real world. Doing so will not only drive manufacturers, network operators and service providers into a new realm of quality customer assurance but, it will also help to create a new means of connectivity that will redefine the way in which we, as a global society, communicate.