WiMAX Eyes Mobile Device Sector

By Cheryl Ajluni

In its purest form, an embedded system contains both a hardware and software component. Choosing the proper components can often be the toughest decision the system engineer has to make. Today that choice is further complicated by the decision regarding which standard to implement. Make the wrong choice and you run the risk of minimizing the life cycle of your embedded solution - worse yet, it may even become obsolete before it has a chance to hit the market.

The standard that currently has captured the communications industry’s attention is the Worldwide Interoperability for Microwave Access (WiMAX) specification (IEEE 802.16). WiMAX provides a high-throughput broadband connection at speeds of up to 75 Mbps over a distance as far as 30 miles, although a WiMAX base-station installation will more likely cover only 3 to 5 miles. WiMAX technology can be used for a number of applications including a “last mile” broadband connection, hotspot and cellular backhaul, and high-speed enterprise connectivity for businesses.

Some analysts believe that WiMAX will become the third most widely used high-speed Internet access technology, following its two key competitors - digital subscriber line (DSL) and cable modem. Many in the industry hold out hope that the technology will deliver on this vision. Others wonder, albeit quietly, if WiMAX’s ability to deliver excellent broadband wireless performance will really turn the market in its favor, despite its initial expense and until such a time that volume sales drive costs down. Or, will the market remain faithful to DSL and cable modem technologies, if for no other reason than that they work just well enough to get the job done?

The Market Outlook

There is little doubt that WiMAX is a viable broadband-wireless-access (BWA) solution or that in certain parts of the world there is a compelling need for its capabilities. The market outlook for the technology seems to support this belief. Consider, for example, that by 2008 worldwide sales of WiMAX equipment will reach billions of dollars. According to semiconductor market research firm iSuppli (El Segundo, CA), worldwide revenue from WiMAX-related base station and CPE sales will achieve annual growth rates of 14-25 percent from 2004 through 2007. From 2008 to 2009, sales will rise by 47 and 66 percent, respectively. By 2009, the market will swell to $2.6 billion in size, growing at a compound-annual-growth rate (CAGR) of 31.3 percent from the $503 million recorded in 2003. Market research firm In-Stat (San Jose, CA) adds that of the billions of dollars of WiMAX equipment sales by 2008, more than half of it will come from CPE sales.

Part of what makes WiMAX such a compelling sell is its ability to make BWA cheaper and easier to deploy (see the Figure). It requires few truckrolls due to good non line-of-sight protocols and offers lots of ratcheting in bandwidth for discrete services. However, some analysts emphasize that this cost savings won’t be realized unless WiMAX providers find a way to bundle wireless broadband services with Voice over Internet Protocol (VoIP). By doing so, customers should be able to reap the reward in terms of a lower monthly bill, despite the initial investment involved in upgrading from dial-up Internet access to broadband.

Trouble May Lie Ahead

Despite this compelling market research, doubts linger as to how quickly WiMAX will actually take hold in the marketplace and which companies will emerge as market leaders. Industry giants Intel (Santa Clara, CA) and Fujitsu Microelectronics (Sunnyvale, CA) have already made their intentions on this space clear. But they are not without competition from companies like WaveSat (Montreal, Canada), which recently announced the general availability of the world’s first 802.16-2004 Rev D compliant WiMAX chip (DM256 baseband IC). A plethora of start-ups such as Beecem Communications (Bangalore, India) and Runcom Technologies (Rishon Lezion, Israel) are also hoping to stake a claim in this market, primarily by going after what many perceive as the real prize - the mobile market of end-user devices.

The mobile version of the WiMAX standard, 802.16(e), will allow mobile WiMAX to be built into notebooks and other mobile devices. It is expected to be ratified sometime during the second half of 2005, and will be quickly followed by product samples, certification, and a volume rollout. The WiMAX Forum’s tentative timetable calls for mobile WiMAX trials to begin the second half of 2006. Interoperability trials, otherwise known as “plugfests” will also need to take place.

As the countdown on this timetable ticks away, chipset makers are beginning to align themselves behind different proposed 802.16(e) modulation schemes. While orthogonal frequency division multiplexing (OFDM) was chosen as the modulation scheme for 802.16 fixed applications, the modulation scheme for 802.16(e) is still up for debate.

The front-runner, scalable OFDM access (OFDMA), is being touted by companies such as Intel, which feels that the modulation scheme can handle the four-fold increase in complexity over fixed WiMAX, different power and coverage requirements, and higher link budgets that are all specific to 802.16(e).

Wavesat is backing another approach, OFDM 256 Fast Fourier Transform (FFT), as a means of guaranteeing backward compatibility to 802.16. According to the company, if it serves as the physical layer in both fixed and mobile WiMAX systems then future base stations should be able to recognize and operate both fixed and mobile applications. This assumes that the physical layer has, at minimum, the same number of carriers (256) and Fast Fourier Transforms.

According to In-Stat, WiMAX is expected to do well as a way to provide Point-to-Point (PtP) links. A prime example would be with cellular BTSs that are currently using a leased line to provide a backhaul to the network.

The choice of a modulation scheme for 802.16(e) is a crucial decision, as it will surely impact the operators’ desires to implement WiMAX. Choosing a scheme that provides them the assurance of backwards compatibility to fixed WiMAX solutions, while also allowing them to preserve their initial 802.16 investment, will be key.

WiMAX is still in its infancy. The first 802.16-2004 Rev D compliant WiMAX chip has only recently been introduced. No WiMAX equipment has been sold. The 802.16(e) specification has yet to be ratified and interoperability testing on 802.16 is not expected until later in 2005.

At the end of the day, there are about as many uncertainties over the future of WiMAX as there are hopes for its ultimate success. One thing is certain, WiMAX will need to prove itself in terms of Quality of Service (QoS) and the ability to adequately deal with interference issues if it hopes to make its mark. For any system engineer looking to incorporate WiMAX into an embedded system, pay close attention to what transpires with 802.16(e) in 2005. With the mobile market expected to make up the largest portion of the total WiMAX market, the choice of a modulation scheme and ratification of the specification promise to have a profound impact on future WiMAX-enabled embedded systems.

Cheryl Ajluni is the owner of Custom Media Solutions, specializing in technology-based content for publications and tradeshows. She has over 10 years experience covering the high-tech industry for such publications as Electronic Design and Embedded Systems Development and served as Editor in Chief of Wireless Systems Design. She has also worked in various engineering roles, holds a patent for the development of a solar cell detection system, and has a Bachelor of Science degree in physics and mathematics from the University of California, Davis.